diff --git a/platform/.golangci.yml b/platform/.golangci.yml
new file mode 100644
index 00000000..e467960e
--- /dev/null
+++ b/platform/.golangci.yml
@@ -0,0 +1,64 @@
+# golangci-lint configuration for the platform module. Pinned to 2.12.2 (Makefile enforces it):
+# findings are version-dependent, so an unpinned linter is not a gate.
+#
+# The enable list is the backend's minus the linters whose finding classes this module does not
+# have yet, plus the SQL ones, which it does. Exclusions are written out rather than taken from a
+# preset: a preset also silences things we want to hear about.
+version: "2"
+
+linters:
+  default: none
+  enable:
+    - errcheck
+    - govet
+    - ineffassign
+    - staticcheck
+    - unused
+    # zero-cost bug classes for an HTTP + Postgres service
+    - bodyclose
+    - copyloopvar
+    - durationcheck
+    - errorlint
+    - makezero
+    - misspell
+    - nilerr
+    - noctx # a request without a context is a request that cannot be cancelled
+    - rowserrcheck
+    - sqlclosecheck
+    - nolintlint # no silent suppressions
+
+  settings:
+    staticcheck:
+      checks:
+        - all
+        - -ST1000 # default-off in golangci-lint: package comment form
+        - -ST1003 # default-off: naming conventions
+        - -ST1016 # default-off: receiver name consistency
+        - -ST1020 # default-off: comment form on exported methods
+        - -ST1021 # default-off: comment form on exported types
+        - -ST1022 # default-off: comment form on exported vars
+    nolintlint:
+      require-explanation: true
+      require-specific: true
+      allow-unused: false
+
+  exclusions:
+    rules:
+      # Close on a reader or a pool handle: nothing actionable comes back. This module has no
+      # flush-on-Close writer, so it cannot hide a lost write.
+      - linters: [errcheck]
+        text: 'Error return value of `[^`]*\.Close` is not checked'
+      # noctx exists to catch an uncancellable OUTBOUND call. httptest.NewRequest builds a request
+      # that is served in-process and never leaves it, so the rule fires 11 times and means nothing
+      # here; production code stays covered.
+      - linters: [noctx]
+        path: _test\.go
+        text: 'httptest\.NewRequest must not be called'
+
+formatters:
+  enable:
+    - gofmt
+
+issues:
+  max-issues-per-linter: 0 # never truncate: a hidden tail reads as "clean"
+  max-same-issues: 0
diff --git a/platform/BACKLOG.md b/platform/BACKLOG.md
index 9ea6e17e..a4bc09cb 100644
--- a/platform/BACKLOG.md
+++ b/platform/BACKLOG.md
@@ -2,6 +2,10 @@
 
 > Ведёт зона `platform/` (решение владельца 02.08, D39.84: фронт и платформа держат СВОИ бэклоги; единый бэклог `docs/PROGRESS.md` остаётся трекером движка/полигона/доков и фронт/платформа-строк не принимает). Нормы те же: ID стабилен навсегда, каждая петля получает диспозицию. Запросы к ДВИЖКУ сюда не пишутся — они заходят строками единого бэклога через оркестратора (пример: строки 99–102). Засеян оркестратором при лендинге D39.84 — дальше правит платформа-сессия.
 
+> **Диспозиции после P0 (04.08)** — в журнале зоны, раздел «Диспозиции бэклога зоны»
+> (`docs/platform-PROGRESS.md`): П-1 начата (каркас), П-2/П-3 не трогали, П-4 черновая схема,
+> П-5 форма предложена. Дублировать их здесь не стали — у строки один источник истины.
+
 | ID | Хвост | Вес | Источник |
 |---|---|---|---|
 | П-1 | **HTTP/SSE-слой и сервисная обвязка** (экс-строка 96 единого бэклога): read-API поверх готовых `OpenReadOnly`-путей движка; SSE-события ПУШИТ воркер, фронт read-model не опрашивает (каждый read-вызов движка — дорогой ре-ингест, до строки 100 единого); аутентификация ратифицирована D39.84: одна серверная сессия в Postgres — `__Host`-кука браузеру · `Authorization: Bearer` десктопу/CLI · principal создаётся ТОЛЬКО в middleware, CSRF только на cookie-пути; ⚠ порядок деплоя: read-путь движка схему НЕ мигрирует (`store.go:135-143`, «schema vN … expects vM») — после апгрейда бинарника по каждой книге первой идёт write-команда; **форма потока ратифицирована D39.85 (`docs/research/23`):** воркер-обёртка платформы супервайзит процесс tmctl, ингестит NDJSON-события идемпотентным апсертом (run_id, seq) в Postgres (Reporting Database, не полный CQRS), SSE — из Postgres; ре-синк на обрыве — `tmctl status --json`; живой SQLite движка НЕ читать (анти-паттерн, аргументы в research/23 §4); ревью-гард: путь Go-модуля платформы никогда не вкладывать под `textmachine/backend/*` | Ф3, после контракта API (строка 95 единого) | D39.81, D39.84, D39.85, STACK_DECISIONS §5 |
diff --git a/platform/Makefile b/platform/Makefile
new file mode 100644
index 00000000..18cc13f8
--- /dev/null
+++ b/platform/Makefile
@@ -0,0 +1,50 @@
+# Platform battery as one command: `make check` is what CI calls and what a session runs before
+# handing the tree over. Toolchain and linter are PINNED (never "latest"): a gate that changes
+# under you on someone else's machine is not a gate. Shape mirrors backend/Makefile deliberately.
+
+GO ?= go
+# go.mod's floor is 1.26.4 (the engine's), but the BUILD toolchain floor here is 1.26.5: it carries
+# the crypto/tls and os security fixes, and this module is the one exposed to the network.
+GO_MIN_VERSION := 1.26.5
+GOLANGCI_LINT ?= golangci-lint
+GOLANGCI_VERSION := 2.12.2
+
+.PHONY: build vet fmt lint test check tools-check vuln
+
+build: tools-check
+	$(GO) build ./...
+
+vet:
+	$(GO) vet ./...
+
+# `gofmt -l` exits 0 even when it names files, so the emptiness of its output is the assertion.
+fmt:
+	@test -z "$$(gofmt -l .)" || { echo "gofmt: not formatted:"; gofmt -l .; exit 1; }
+
+tools-check:
+	@$(GO) version | grep -qE 'go1\.26\.([5-9]|[0-9]{2,})|go1\.(2[7-9]|[3-9][0-9])' || { \
+		echo "Go $(GO_MIN_VERSION)+ required (security fixes in a network-facing module); got: $$($(GO) version)"; exit 1; }
+	@$(GOLANGCI_LINT) --version 2>/dev/null | grep -q " $(GOLANGCI_VERSION) " || { \
+		echo "golangci-lint $(GOLANGCI_VERSION) required (findings are version-dependent)."; \
+		echo "install: https://github.com/golangci/golangci-lint/releases/tag/v$(GOLANGCI_VERSION)"; exit 1; }
+
+lint: tools-check
+	$(GOLANGCI_LINT) run --timeout=10m ./...
+
+# -race needs cgo. If the C toolchain is missing this fails loudly rather than quietly proving less.
+test:
+	$(GO) test ./... -race -count=1
+
+# The battery. It ends by NAMING the tests that did not run: the database-backed ones skip without
+# TM_PLATFORM_TEST_DSN, and a silent skip reads as coverage.
+check: build vet fmt lint test
+	@echo "--- did NOT run (no database; set TM_PLATFORM_TEST_DSN) ---"
+	@$(GO) test ./... -count=1 -v > .skips.log 2>&1 || { echo "the skip-harvest pass FAILED:"; \
+		grep -E '^(---|\s+---) FAIL|^FAIL' .skips.log; rm -f .skips.log; exit 1; }
+	@grep -- '--- SKIP' .skips.log || echo "(none)"
+	@rm -f .skips.log
+
+# Not part of `check`: it needs the network (the vulnerability database), and the battery must be
+# green on a bare clone offline. CI runs it as its own step (STACK_DECISIONS §5).
+vuln:
+	$(GO) run golang.org/x/vuln/cmd/govulncheck@v1.6.0 ./...
diff --git a/platform/README.md b/platform/README.md
index ca6d12d9..aab12912 100644
--- a/platform/README.md
+++ b/platform/README.md
@@ -1,6 +1,12 @@
 # platform — control plane (SaaS-слой)
 
-Зона записи сессии «Платформа». Кода ещё нет; **активный промт — `docs/PLATFORM_SESSION_PROMPT.md` (P0, выдан 04.08, D39.100)**, зонный журнал — `docs/platform-PROGRESS.md` (весь прогресс зоны здесь, решение владельца 04.08).
+Зона записи сессии «Платформа». P0 собран 04.08 (скелет: HTTP · сессии · схема read-model ·
+интерфейс ингеста); **активный промт — `docs/PLATFORM_SESSION_PROMPT.md`**, зонный журнал —
+`docs/platform-PROGRESS.md` (весь прогресс зоны здесь, решение владельца 04.08), стек —
+`docs/STACK_DECISIONS.md`.
+
+Батарея зоны: `make check` (build · vet · fmt · lint · test -race). Тесты со схемой требуют
+`TM_PLATFORM_TEST_DSN`; без него они пропускаются, и `check` называет пропуски вслух.
 
 ## ⚠ Git и зона (читать ДО первой строки кода)
 
@@ -42,11 +48,12 @@
 
 ## Стек
 
-Пины и обоснования — [`../frontend/docs/STACK_DECISIONS.md`](../frontend/docs/STACK_DECISIONS.md) §5
-(общий документ решений по обоим новым сервисам; исследование 02.08).
+Пины, даты релизов и обоснования — [`docs/STACK_DECISIONS.md`](docs/STACK_DECISIONS.md) (зонный,
+live-сверка 04.08); общая записка по обоим новым сервисам — `../frontend/docs/STACK_DECISIONS.md` §5.
 
-Коротко: Go 1.26.4 · стандартный `net/http` + `ServeMux` без роутер-библиотеки · pgx v5.10.0 ·
-goose v3.27.3 · очередь River v0.42.0 на том же Postgres · `govulncheck` гейтом CI.
+Коротко: Go 1.26.4 в `go.mod` (тулчейн сборки ≥1.26.5) · стандартный `net/http` + `ServeMux` без
+роутер-библиотеки · PostgreSQL 18 · pgx v5.10.0 · goose v3.27.3 · очередь River v0.42.0 на том же
+Postgres (запинена, ещё не подключена — П-3) · `govulncheck` отдельной целью.
 **Redis не заводим нигде** — зафиксировано как архитектурное «нет».
 
 Прогресс наружу — SSE, события **пушит воркер**, а не фронт опрашивает read-model.
diff --git a/platform/cmd/tmplatformd/main.go b/platform/cmd/tmplatformd/main.go
new file mode 100644
index 00000000..856664ce
--- /dev/null
+++ b/platform/cmd/tmplatformd/main.go
@@ -0,0 +1,103 @@
+// Command tmplatformd is the TextMachine control plane: HTTP for the frontend, Postgres for the
+// read model, and (from P-1 onward) a worker that supervises tmctl processes. It contains no
+// translation logic: the engine is spawned, never linked (D39.81).
+package main
+
+import (
+	"context"
+	"errors"
+	"log/slog"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"textmachine/platform/internal/auth"
+	"textmachine/platform/internal/config"
+	"textmachine/platform/internal/httpapi"
+	"textmachine/platform/internal/pgstore"
+)
+
+func main() {
+	// Structured logs on stderr, like the engine's: stdout stays free for anything machine-read.
+	log := slog.New(slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelInfo}))
+	if err := run(log); err != nil {
+		log.Error("fatal", "err", err)
+		os.Exit(1)
+	}
+}
+
+func run(log *slog.Logger) error {
+	cfg, err := config.Load()
+	if err != nil {
+		return err
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	var db *pgstore.Store
+	if cfg.DSN == "" {
+		// Deliberate: the process still serves liveness so a supervisor can start it before the
+		// database exists. /readyz is the honest signal, and it says no.
+		log.Warn("no TM_PLATFORM_DSN: starting without a database, /readyz will report not ready")
+	} else {
+		if cfg.Migrate {
+			if err := pgstore.Migrate(ctx, cfg.DSN); err != nil {
+				return err
+			}
+			log.Info("migrations applied")
+		}
+		if db, err = pgstore.Open(ctx, cfg.DSN); err != nil {
+			return err
+		}
+		defer db.Close()
+	}
+
+	authn := &auth.Authenticator{
+		IdleTTL: cfg.SessionIdleTTL,
+		Deny:    httpapi.ProblemHandler(http.StatusUnauthorized, "Session missing or invalid"),
+	}
+	deps := httpapi.Deps{Log: log, Auth: authn, TrustedOrigins: cfg.TrustedOrigins}
+	if db != nil {
+		deps.DB = db
+		authn.Sessions = db
+	}
+	handler, err := httpapi.New(deps)
+	if err != nil {
+		return err
+	}
+
+	srv := &http.Server{
+		Addr:    cfg.Addr,
+		Handler: handler,
+		// No WriteTimeout: the SSE stream (P-1) is a long-lived response, and a write deadline set
+		// here would cut it. Per-request deadlines belong on the handlers that want them.
+		ReadHeaderTimeout: 10 * time.Second,
+		IdleTimeout:       2 * time.Minute,
+		MaxHeaderBytes:    1 << 16,
+		BaseContext:       func(net.Listener) context.Context { return ctx },
+	}
+
+	errc := make(chan error, 1)
+	go func() {
+		log.Info("listening", "addr", cfg.Addr)
+		errc <- srv.ListenAndServe()
+	}()
+
+	select {
+	case err := <-errc:
+		if errors.Is(err, http.ErrServerClosed) {
+			return nil
+		}
+		return err
+	case <-ctx.Done():
+		stop() // a second signal now kills instead of waiting
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
+		defer cancel()
+		log.Info("shutting down")
+		return srv.Shutdown(shutdownCtx)
+	}
+}
diff --git a/platform/docs/STACK_DECISIONS.md b/platform/docs/STACK_DECISIONS.md
new file mode 100644
index 00000000..f2d28edf
--- /dev/null
+++ b/platform/docs/STACK_DECISIONS.md
@@ -0,0 +1,64 @@
+# Стек платформы — пины и обоснования
+
+> Зонный документ `platform/`. Пины ниже сверены ЖИВЬЁМ 04.08.2026 (Go-прокси `@latest`,
+> postgresql.org, go.dev/dl) — версии по памяти не называются. Библиотеки сессия не ратифицирует:
+> таблица уходит оркестратору вместе с деревом.
+>
+> Общая записка по обоим новым сервисам — `frontend/docs/STACK_DECISIONS.md` §5 (02.08). Здесь —
+> платформенная часть с датами релизов и сверкой. Что изменилось за два дня: три библиотечных пина
+> §5 (pgx · goose · River) на 04.08 всё ещё последние; по Go последним патчем стенда идёт 1.26.5
+> (07.07) — floor `go.mod` оставлен общим с движком, а тулчейн сборки поднят до 1.26.5 (см. ниже).
+
+## Пины
+
+| Что | Пин | Релиз пина | Зачем нам |
+|---|---|---|---|
+| Go (язык, `go.mod`) | **1.26.4** | 02.06.2026 | Тот же floor, что у движка (`backend/go.mod`) — общий стенд собирает оба модуля одним тулчейном |
+| Go (тулчейн сборки, `make tools-check`) | **≥1.26.5** | 07.07.2026 | 1.26.5 несёт security-фиксы `crypto/tls` и `os`; сетевой модуль собирается ими, а не «чем-нибудь 1.26» |
+| PostgreSQL | **18.x** (проверено на 18.4), floor **16** | 18.4 — май 2026 | 18 — текущая мажорная (19 в бете, в прод не берём); floor 16, потому что River тестируется на трёх последних мажорных |
+| HTTP | stdlib `net/http` + `ServeMux` | — | Роутер-библиотека не нужна: `ServeMux` с 1.22 умеет метод+wildcards, а `Request.Pattern` даёт лог по маршруту, не по пути |
+| CSRF | stdlib `http.CrossOriginProtection` | Go 1.25 | Ровно тот механизм, что описан в §5 (Sec-Fetch-Site → Origin), теперь в тулчейне — свой велосипед не пишем |
+| Postgres-драйвер | `github.com/jackc/pgx/v5` **v5.10.0** | 03.06.2026 | Живой pool, `pgconn.PgError` для проверки констрейнтов, `stdlib` для goose |
+| Миграции | `github.com/pressly/goose/v3` **v3.27.3** | 22.07.2026 | Библиотекой + `embed.FS`; `WithSessionLocker` = advisory-лок, две реплики выкатываются по очереди |
+| Очередь | `github.com/riverqueue/river` **v0.42.0** | 31.07.2026 | Пин ПОДТВЕРЖДЁН живой сверкой, но **в `go.mod` НЕ добавлен**: П-3 вне скоупа P0, а зависимость без кода — мусор в графе |
+| Линтер | `golangci-lint` **2.12.2** | 06.05.2026 | Тот же пин, что у движка: находки версионно-зависимы, разъезд пинов = разные гейты в одном репо |
+| Уязвимости | `govulncheck` **v1.6.0** | 09.07.2026 | Отдельная цель `make vuln`, не часть `check`: ей нужна сеть, а батарея обязана быть зелёной на голом клоне офлайн |
+
+**Redis нет** — архитектурное «нет» из §5 в силе: очередь, лизы и рейт-лимиты живут в том же Postgres.
+
+## Что решено этой сессией (сверх §5)
+
+1. **`/healthz` ≠ `/readyz`.** Liveness ничего не трогает (БД лежит — процесс жив), readiness пингует
+   пул. Пустой `TM_PLATFORM_DSN` — легальный старт: сервис поднимается и честно говорит «не готов».
+   Иначе супервизор убивает здоровый процесс за то, что база моргнула.
+2. **Ops-эндпоинты вне версионного префикса.** `/healthz`, `/readyz` — в корне; контрактная
+   поверхность целиком под `/v0` (базовый путь спеки платформа ПОДТВЕРЖДАЕТ).
+3. **Один mux.** Контрактные маршруты регистрируются с префиксом в паттерне, а не вложенным mux'ом
+   под `StripPrefix`: вложенный получает КОПИЮ запроса, и `Request.Pattern` наружу не возвращается —
+   лог пришлось бы писать по сырому пути с id книг. Проверено исполнением.
+4. **Гард навешен на поддерево, а не на ручки.** Неизвестный путь под `/v0` отвечает 401 раньше 404:
+   аноним не должен картографировать поверхность.
+5. **Заголовки безопасности — на каждом ответе** (`X-Robots-Tag: noindex`, `Cache-Control: no-store`,
+   `nosniff`, `no-referrer`): ПТ-34 нельзя оставлять на дисциплину автора следующей ручки.
+6. **Батарея зоны — `make check`** (build · vet · fmt · lint · test -race), форма скопирована с
+   `backend/Makefile` вплоть до именования пропущенных тестов: тихий skip читается как покрытие.
+7. **Тесты с БД гейтятся `TM_PLATFORM_TEST_DSN`** и создают СВОЮ базу на прогон (дропают в
+   `t.Cleanup`). Батарея на голом клоне зелёная и офлайн; с DSN — та же батарея плюс схема.
+
+## Как поднять локально
+
+```sh
+export TM_PLATFORM_DSN='postgres://user@host:5432/tmplatform?sslmode=disable'
+make check                        # батарея зоны
+TM_PLATFORM_MIGRATE=1 go run ./cmd/tmplatformd   # миграции + сервер на 127.0.0.1:8080
+curl -s localhost:8080/healthz    # ok
+curl -s localhost:8080/readyz     # ready
+```
+
+Переменные: `TM_PLATFORM_ADDR` · `TM_PLATFORM_DSN` · `TM_PLATFORM_MIGRATE` ·
+`TM_PLATFORM_TRUSTED_ORIGINS` (через запятую) · `TM_PLATFORM_SESSION_IDLE` ·
+`TM_PLATFORM_SESSION_MAX_AGE`.
+
+⚠ Postgres на стенде отсутствует как системный пакет и sudo нет. Схема и запросы этой сессии
+проверены на ЖИВОМ PostgreSQL **18.4**, поднятом без root из бинарников zonky
+(`io.zonky.test.postgres`, Maven Central) в скрэтчпаде — вне репозитория и вне зависимостей модуля.
diff --git a/platform/docs/platform-PROGRESS.md b/platform/docs/platform-PROGRESS.md
index b50a1ead..8961784f 100644
--- a/platform/docs/platform-PROGRESS.md
+++ b/platform/docs/platform-PROGRESS.md
@@ -6,14 +6,200 @@
 
 ## Текущее состояние
 
-- Кода нет. `go.mod` заведён. Промт P0 выдан 04.08 (`PLATFORM_SESSION_PROMPT.md`, D39.100).
-- Контракт API v0 ратифицирован (D39.99, `docs/architecture/14-api-contract/`) — на платформе
-  дизайн-ответы К-4 (ревизия) · К-7 (пагинация) · К-12 (пуш экспорта) · форма П-5 (лимиты).
+- **P0 собран** (сессия 04.08): модуль компилируется, батарея зоны `make check` зелёная,
+  `/healthz` и `/readyz` проверены живым запуском против живого Postgres 18.4.
+- Стек запинен и live-сверен — `STACK_DECISIONS.md` (зонный).
+- Дизайн-ответы К-4 · К-7 · К-12 · форма П-5 — ниже, ПРЕДЛОЖЕНИЯМИ на ратификацию.
+- Контрактных ручек нет намеренно: они ждут ратификации К-4/К-7 (форма ответов) — это П-1.
 
 ## Открытые вопросы к владельцу/оркестратору
 
-_(пусто)_
+1. **⚠ ВЛАДЕЛЬЦУ (П-5).** При сбросе окна лимитов приостановленный (`paused`) перевод
+   продолжается САМ или ждёт явного «Продолжить»? От ответа зависит, есть ли кнопка на экране и
+   нужно ли уведомление «продолжили без вас». Технически дёшевы оба варианта.
+2. **Оркестратору (контракт).** Поток событий привязан к ПРОГОНУ (`/runs/{runId}/events`), а
+   статусы `uploading`/`parsing` существуют ДО прогона, и библиотека охватывает книги без прогонов.
+   Живого канала у них нет вовсе. Нужна либо строка в спеке «до старта прогона состояние
+   опрашивается», либо пользовательский поток (он же закрыл бы К-12 пушем). Решение — не наше.
+3. **Оркестратору (спека).** Третий слой CSRF из STACK §5 требует от браузерного клиента
+   заголовок `X-TM-Client` на небезопасных запросах cookie-пути. Это требование к ФРОНТУ, и его
+   место — в описании `sessionCookie` в спеке. Реализовано и проверено тестами.
+
+## Дизайн-ответы на ратификацию
+
+### К-4 — ревизия: пер-ресурсная со скоупом КНИГА; чтения её несут
+
+Обе половины вопроса:
+
+1. **Чтения ревизию несут — да.** Без неё правило «отбрось чтение старше уже применённого
+   события» нечем реализовать, а рефетч по возврату фокуса окна включён у `react-query` по
+   умолчанию — то есть гонка на каждое переключение вкладки, а не редкий случай.
+2. **Счётчик — один на КНИГУ.** Все книго-скоупные чтения (карточка, главы, юниты, замечания,
+   банк, прогон) возвращают ОДНО и то же число — `books.revision`, +1 за материализующую
+   транзакцию; строки, которых она коснулась, штампуются новым значением. `id` SSE-кадра прогона —
+   ТО ЖЕ число, поэтому события и чтения книги полностью упорядочены между собой.
+
+Почему книга, а не сквозной счётчик:
+
+- сравнивать ревизии осмысленно только внутри скоупа, а книга — минимальный скоуп, в котором
+  лежит всё, что поток может протухнуть;
+- единственный писатель на книгу уже гарантирован (сериализация очереди по `book_id` — П-3, плюс
+  EXCLUSIVE-лок движка на файл проекта), поэтому счётчику не нужны ни блокировка, ни глобальная
+  последовательность;
+- глобальный счётчик отвергнут по двум причинам: одна горячая последовательность на всех
+  пользователей и утечка — по разрывам номеров любой клиент оценивает активность всей платформы;
+- у библиотеки (`GET /books`) свой скоуп — счётчик на пользователя (`users.library_revision`),
+  потому что она охватывает книги.
+
+Просим внести в спеку прозой: (i) `revision` монотонна В ПРЕДЕЛАХ скоупа ресурса и между скоупами
+не сравнивается; (ii) кадр потока и книго-скоупные чтения несут ОДИН счётчик; (iii) отбрасывание
+устаревшего чтения — обязанность клиента.
+
+Побочная выгода: тот же штамп даёт докачку потока «строки книги с `revision > X`» БЕЗ журнала
+событий — реплей истории остаётся запрещённым (D39.85, контракт §2.11).
+
+### К-7 — курсор на каждом списке, дефолт «одна страница»
+
+Замер (сериализация фикстур контрактной формы, случайные значения — не повторяющиеся, иначе gzip
+льстит): 2284 главы = **289 КБ JSON / 46 КБ gzip**; 1200 терминов = **229 КБ / 40 КБ**. Одним
+ответом влезает — но китайские вебновеллы на 5000+ глав норма, а банк растёт вместе с книгой,
+поэтому «всегда одним ответом» — это отложенное молчаливое обрезание.
+
+Предложение: **keyset-курсор на КАЖДОМ списочном ответе**, параметры `?limit=&cursor=`, поле
+`next_cursor: string|null` присутствует ВСЕГДА. Дефолты: главы 5000 (обычная книга = одна
+страница), банк 1000, замечания 500; юниты и библиотека курсор тоже несут, хотя практически не
+пагинируются.
+
+- **Keyset, не offset:** материализатор пишет параллельно чтению, а offset на пишущейся таблице
+  пропускает и дублирует строки; keyset по `(book_id, number)` устойчив к дозаписи.
+- **Поле с первого дня у всех списков — намеренно.** Добавить его позже — минорное изменение,
+  которое у клиента, его не читающего, молча отрезает хвост.
+- Курсор непрозрачный, кодирует последний ключ сортировки и `revision`; смена `revision` между
+  страницами обязывает клиента начать цикл заново, иначе он склеит два состояния.
+
+### К-12 — опрос; причина структурная, а не вкусовая
+
+Единственный поток контракта привязан к ПРОГОНУ, а экспорт делают с законченной книги — живого
+прогона обычно нет. Пуш завершения потребовал бы второго потока ради одного булева.
+
+Предложение — индустриальный async request-reply: `POST /books/{id}/exports` → `202` +
+`Location`; `GET /books/{id}/exports/{id}` → `200` c `ready:false` и заголовком `Retry-After`, пока
+строится, и `ready:true` + `url`, когда готов. Интервал называет СЕРВЕР, клиент не угадывает.
+Просим добавить `Retry-After` в спеку. Появится пользовательский поток (вопрос 2 выше) — пуш
+поедет им, опрос останется фолбэком.
+
+### П-5 — форма API лимитов/использования
+
+`GET /v0/usage` (страница лимитов в настройках):
+
+```json
+{"revision": 42, "state": "ok|approaching|exhausted", "used_percent": 37,
+ "resets_at": "2026-08-11T00:00:00Z",
+ "windows": [{"period": "day", "used_percent": 12, "resets_at": "…"},
+             {"period": "week", "used_percent": 37, "resets_at": "…"}]}
+```
+
+- **Сумм нет ни в каком виде.** Процент и время сброса — статус использования, а не деньги
+  (D39.84 в силе, механика «как Claude Code» — D39.100/ПТ-35).
+- **Стоп по потолку:** `BookStatus: paused` + машинная причина. Предлагаем
+  `Run.paused_reason: "limits_exhausted" | null`: фразу («перевод остановлен: лимиты исчерпаны»)
+  рисует клиент словами владельца (В-3), API несёт состояние. Без поля причины второй повод для
+  паузы станет ломающим изменением.
+- **Источник цифр.** Поток событий денег не несёт и не должен (кадр `ceiling` — только факт),
+  поэтому платформа метрит из `tmctl status --json` (`committed_usd`) на границах попыток и на
+  ре-синке; хранит целыми микро-долларами в `usage_windows`.
+- **Поднятие потолка — политика платформы, не кнопка на экране.** Платформа сама владеет
+  `book.yaml`, поднимает `ceilings.book_usd` и перезапускает прогон. **Проверено кодом, что это
+  безопасно:** `Ceilings` объявлен в `backend/internal/config/book.go:106`, а в канон `BriefHash`
+  (`:280-297`) НЕ входит — значит поднятие потолка не двигает `brief_hash` → снапшот и не вызывает
+  ни дрифт, ни ре-билл. Риск «подняли лимит — переплатили книгу заново» снят фактом, не надеждой.
+
+## Что построено (P0)
+
+| Кусок | Где | Проверено |
+|---|---|---|
+| Модуль, layout, батарея | `go.mod` (sibling движка, гард D39.85 соблюдён), `Makefile`, `.golangci.yml` | `make check` зелёный: build · vet · gofmt · lint 0 issues · `go test -race` |
+| HTTP-скелет | `internal/httpapi/` | Живой запуск: `/healthz` 200, `/readyz` 200 против живого PG, `/v0/*` 401 problem+json, graceful shutdown по SIGTERM |
+| Заголовки ПТ-34 | `internal/httpapi/middleware.go` | Живой ответ несёт `X-Robots-Tag: noindex, nofollow`, `Cache-Control: no-store`, `nosniff`, `no-referrer` |
+| Сессии П-1 | `internal/auth/` + `internal/pgstore/sessions.go` | Тесты: обе презентации → principal, Bearer > cookie, истечение/отзыв/свип, токен в БД не попадает (только SHA-256), скольжение окна только во второй половине |
+| CSRF | `internal/auth/csrf.go` | stdlib `http.CrossOriginProtection` + обязательный `X-TM-Client` на cookie-пути; 6 кейсов тестом + живой пробой (cookie-POST без заголовка → 403, cross-site → 403) |
+| Схема read-model | `internal/pgstore/migrations/` | Миграции применены на ЖИВОМ PostgreSQL 18.4 дважды (идемпотентность), все констрейнты сработали поимённо |
+| Интерфейс NDJSON-ингеста | `internal/ingest/` | Тесты: хендшейк обязателен, мажор отвергается, минор и незнакомый тип толерируются, разрыв/повтор seq ловятся; супервизор проверен НАСТОЯЩИМ процессом (exit 3 → `bank_stop`, stderr движка в файл, поток материализован) |
+| Ре-синк | `internal/ingest/resync.go` | Тест на фикстуре в форме `pipeline.StatusReport` (имена полей сверены по `backend/internal/pipeline/status.go:37-130`, живого прогона не было): аллоулист берёт своё, деньги/снапшоты игнорируются |
+
+Не построено намеренно: материализатор `Sink → Postgres` (нужен ратифицированный словарь событий,
+иначе перепишется), контрактные ручки и SSE (П-1 после ратификации К-4/К-7), очередь River (П-3),
+брокер лимитов (П-2).
+
+## Находки (грунтованные)
+
+1. **Ключ идемпотентности `(run_id, seq)` работает только если `run_id` — ДВИЖКОВЫЙ.** Resume
+   поднимает новый процесс, его `seq` стартует с 1; если ключом взять платформенный run, high-water
+   mark отбросит весь поток второй попытки. Заведено в схеме: `run_attempts.engine_run_id` (unique)
+   + `last_seq`. Просьба к строке 103: кадр `hello` обязан нести этот id; идеально — вместе со
+   строкой 102 (внешний trace-контекст), тогда id назначает платформа и пространство ключей наше.
+2. **Дыра контракта — статусы до прогона и библиотека без канала.** См. вопрос 2 выше.
+3. **Банк: канала нет — но не полностью.** Подтверждаем находку оркестратора и уточняем состав:
+   сегодня добываемы (а) ПРЕДЛОЖЕННЫЕ термины стопа — сайдкар/строка 101 и (б) термины, которые
+   промотировала сама платформа — она же ПИШЕТ mined-delta и сид. Недобываемы `auto`/`ruby`-строки,
+   материализованные внутри движка. То есть `GET /bank` частично реализуем уже сейчас; полностью —
+   после артефакта экспорта банка.
+4. **Ре-синк не восстанавливает пофазный прогресс:** в `status --json` разбивки нет (строка 99).
+   После обрыва и до следующего события прогресса клиент увидит агрегат. Записано в коде.
+5. **`status --json` — ремонтный путь, не поллинг:** каждый вызов заново ингестит и режет исходник
+   (1.4–1.5 с CPU на книге 23 МБ — замер фронт-сессии 02.08, не наш; строка 100).
+6. **Деньги движка живут в его stderr на уровне INFO.** Поэтому супервизор пишет stderr движка в
+   ФАЙЛ попытки и не тейлит его в структурный лог платформы — иначе суммы попадут в наш INFO
+   (запрет D39.84 + норма P0-промта).
+7. **Мелочи в чужой зоне (не трогали, лендить оркестратору):** в ратифицированной копии
+   `docs/architecture/14-api-contract/openapi.yaml` `info.description` всё ещё называет файл
+   черновиком S3 и ссылается на `../API_CONTRACT_DRAFT.md`; в README той же папки ссылка
+   «нормативная поверхность → `api-contract/openapi.yaml`» бьёт мимо (файл лежит рядом:
+   `./openapi.yaml`). Решения D39.100 (`paused`, `eta_seconds`) в YAML ещё не внесены — это работа
+   S3; схема платформы их уже держит.
+8. **Стенд:** Postgres как системного пакета нет и sudo нет, поэтому схема проверена на живом
+   PostgreSQL 18.4, поднятом БЕЗ root из бинарников zonky в скрэтчпаде (вне репозитория и вне
+   зависимостей модуля). Тесты с БД гейтятся `TM_PLATFORM_TEST_DSN` и создают свою базу на прогон.
+
+## Диспозиции бэклога зоны
+
+| ID | Диспозиция |
+|---|---|
+| П-1 | **НАЧАТА.** Готово: каркас сессий (схема + мидлварь + CSRF), HTTP-скелет, схема read-model, интерфейс ингеста и ре-синка. Осталось: контрактные ручки, SSE-эндпоинт, материализатор `Sink → Postgres`, воркер. Блокеры: ратификация К-4/К-7 (форма ответов), словарь событий (строка 103) |
+| П-2 | Не трогали — гейт «до второго параллельного пользователя» в силе |
+| П-3 | Не строили. В схеме заведён гард: частичный уникальный индекс «один живой прогон на книгу» (`runs_one_live_per_book`) — то, что очередь обязана соблюдать, теперь отказывает база. River запинен, но в `go.mod` НЕ добавлен |
+| П-4 | Схема `usage_windows` заведена драфтом; источник метрик назван (дельты `committed_usd` из `status --json`). Гейт бюджета ДО старта — вместе с очередью |
+| П-5 | Форма предложена выше. Ждёт ответа владельца по авто-продолжению (вопрос 1) |
 
 ## Хроника
 
 _(записи сессий — сверху новые)_
+
+### 04.08.2026 — сессия P0 (платформа №1)
+
+Прочитано: `CLAUDE.md`, `research/23`, контракт `14-api-contract` (README + openapi.yaml целиком),
+`platform/BACKLOG.md`, `frontend/docs/STACK_DECISIONS.md` §5, D39.81/84/85/99/100 по grep.
+
+Сделано: стек live-сверен (три библиотечных пина §5 — pgx · goose · River — на 04.08 всё ещё
+последние; по Go последний патч 1.26.5 от 07.07, floor модуля оставлен общим с движком) →
+модуль наполнен →
+скелет HTTP + сессии + CSRF → схема read-model тремя миграциями → интерфейс ингеста/супервизии/
+ре-синка → батарея зоны → дизайн-ответы (выше).
+
+Ревью исполнением: `make check` зелёный; сервер поднят живьём против живого PostgreSQL 18.4 и
+опрошен curl'ом (healthz/readyz/401/CSRF-403); миграции применены дважды; констрейнты проверены
+поимённо через `pgconn.PgError.ConstraintName`; супервизор проверен настоящим процессом с
+контрактными кодами возврата.
+
+Адверсариальная самопроверка (author≠reviewer) дала четыре правки, каждая внесена:
+(а) вложенный mux под `StripPrefix` терял `Request.Pattern`, из-за чего лог писался бы по сырому
+пути с id книг — проверено экспериментом, переделано на один mux; (б) отклонённые запросы (401/403)
+вообще не логировались, потому что лог висел на маршрутах, а гард стоял снаружи — лог поднят
+наружу, добавлен тест «денайл тоже виден»; (в) **дефект, найденный запуском бинарника без БД:**
+предъявленный Bearer уходил в nil-хранилище сессий и падал паникой в 500 — теперь отсутствие
+хранилища это отказ 401, как и любой другой промах (регрессионный тест на месте); (г) пин тулчейна
+поднят до 1.26.5 — в нём security-фиксы `crypto/tls` и `os`, а этот модуль сетевой (в `go.mod`
+floor остался 1.26.4, общий с движком). Плюс снят мёртвый код: `crypto/rand.Read` по доке ошибку
+не возвращает вовсе (падает), поэтому ветки её обработки убраны, а не оставлены изображать проверку.
+
+Дерево не коммичено — лендит оркестратор.
diff --git a/platform/go.mod b/platform/go.mod
index d5b23fea..ce9cfdca 100644
--- a/platform/go.mod
+++ b/platform/go.mod
@@ -1,3 +1,19 @@
 module textmachine/platform
 
 go 1.26.4
+
+require (
+	github.com/jackc/pgx/v5 v5.10.0
+	github.com/pressly/goose/v3 v3.27.3
+)
+
+require (
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/mfridman/interpolate v0.0.2 // indirect
+	github.com/sethvargo/go-retry v0.4.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	golang.org/x/sync v0.22.0 // indirect
+	golang.org/x/text v0.40.0 // indirect
+)
diff --git a/platform/go.sum b/platform/go.sum
new file mode 100644
index 00000000..62dfbd71
--- /dev/null
+++ b/platform/go.sum
@@ -0,0 +1,54 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
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diff --git a/platform/internal/auth/csrf.go b/platform/internal/auth/csrf.go
new file mode 100644
index 00000000..98a78977
--- /dev/null
+++ b/platform/internal/auth/csrf.go
@@ -0,0 +1,61 @@
+package auth
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// ClientHeader is the header a browser client must send with every unsafe cookie-authenticated
+// request. Any value; its PRESENCE is the assertion.
+const ClientHeader = "X-TM-Client"
+
+// CSRF guards the cookie path and only it: a Bearer token is not ambient authority, so no
+// cross-site page can make a browser attach one.
+//
+// Two layers, both cheap:
+//
+//   - http.CrossOriginProtection (stdlib, Go 1.25+) — Sec-Fetch-Site with an Origin/Host fallback.
+//     This is the mechanism STACK_DECISIONS §5 describes, and it now ships with the toolchain, so
+//     we do not hand-roll it.
+//   - a required custom header on unsafe requests that carry the session cookie. The stdlib check
+//     ALLOWS a request bearing neither Sec-Fetch-Site nor Origin, on the reasoning that it is not
+//     a browser. A pre-2023 browser posting a cross-site <form> is exactly that case, and
+//     POST /books takes multipart/form-data — a form-reachable content type that triggers no
+//     preflight. A plain form cannot set a custom header; a fetch() from our own origin can.
+//
+// trustedOrigins are additional origins allowed to make unsafe requests (a separately deployed
+// frontend). Empty means same-origin only. deny writes the 403 body — injected for the same reason
+// as Authenticator.Deny: the error shape belongs to the API layer.
+func CSRF(trustedOrigins []string, deny http.Handler) (func(http.Handler) http.Handler, error) {
+	p := http.NewCrossOriginProtection()
+	p.SetDenyHandler(deny)
+	for _, o := range trustedOrigins {
+		if err := p.AddTrustedOrigin(o); err != nil {
+			return nil, fmt.Errorf("auth: trusted origin %q: %w", o, err)
+		}
+	}
+	return func(next http.Handler) http.Handler {
+		return p.Handler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			if cookieUnsafe(r) && r.Header.Get(ClientHeader) == "" {
+				deny.ServeHTTP(w, r)
+				return
+			}
+			next.ServeHTTP(w, r)
+		}))
+	}, nil
+}
+
+// cookieUnsafe reports a state-changing request presented by cookie. It reads the cookie directly
+// rather than the principal: this check runs BEFORE authentication, so that a forged request is
+// refused without touching the session table.
+func cookieUnsafe(r *http.Request) bool {
+	switch r.Method {
+	case http.MethodGet, http.MethodHead, http.MethodOptions:
+		return false
+	}
+	if r.Header.Get("Authorization") != "" {
+		return false
+	}
+	c, err := r.Cookie(CookieName)
+	return err == nil && c.Value != ""
+}
diff --git a/platform/internal/auth/csrf_test.go b/platform/internal/auth/csrf_test.go
new file mode 100644
index 00000000..5ef1deec
--- /dev/null
+++ b/platform/internal/auth/csrf_test.go
@@ -0,0 +1,71 @@
+package auth
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func csrfChain(t *testing.T, trusted ...string) (http.Handler, *bool) {
+	t.Helper()
+	passed := false
+	mw, err := CSRF(trusted, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusForbidden)
+	}))
+	if err != nil {
+		t.Fatal(err)
+	}
+	return mw(http.HandlerFunc(func(http.ResponseWriter, *http.Request) { passed = true })), &passed
+}
+
+func TestCSRF(t *testing.T) {
+	cases := []struct {
+		name    string
+		method  string
+		headers map[string]string
+		cookie  bool
+		trusted []string
+		want    int
+	}{
+		{name: "same-origin write with the client header", method: http.MethodPost, cookie: true,
+			headers: map[string]string{"Sec-Fetch-Site": "same-origin", ClientHeader: "web"}, want: http.StatusOK},
+		{name: "cross-site write rejected by the stdlib guard", method: http.MethodPost, cookie: true,
+			headers: map[string]string{"Sec-Fetch-Site": "cross-site", ClientHeader: "web"}, want: http.StatusForbidden},
+		// The hole the stdlib guard leaves open on purpose: no Sec-Fetch-Site, no Origin. A
+		// pre-2023 browser posting a cross-site multipart form looks exactly like this.
+		{name: "headerless cookie write rejected by the client header", method: http.MethodPost, cookie: true,
+			want: http.StatusForbidden},
+		{name: "bearer write needs no client header", method: http.MethodPost,
+			headers: map[string]string{"Authorization": "Bearer t"}, want: http.StatusOK},
+		{name: "reads are never blocked", method: http.MethodGet, cookie: true, want: http.StatusOK},
+		{name: "trusted origin allowed", method: http.MethodPost, cookie: true, trusted: []string{"https://app.example.org"},
+			headers: map[string]string{"Sec-Fetch-Site": "cross-site", "Origin": "https://app.example.org", ClientHeader: "web"},
+			want:    http.StatusOK},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			h, passed := csrfChain(t, tc.trusted...)
+			r := httptest.NewRequest(tc.method, "/v0/books", nil)
+			for k, v := range tc.headers {
+				r.Header.Set(k, v)
+			}
+			if tc.cookie {
+				r.AddCookie(&http.Cookie{Name: CookieName, Value: "t"})
+			}
+			w := httptest.NewRecorder()
+			h.ServeHTTP(w, r)
+			if w.Code != tc.want {
+				t.Fatalf("status = %d, want %d", w.Code, tc.want)
+			}
+			if got := *passed; got != (tc.want == http.StatusOK) {
+				t.Fatalf("handler reached = %v", got)
+			}
+		})
+	}
+}
+
+func TestCSRFRejectsAMalformedTrustedOrigin(t *testing.T) {
+	if _, err := CSRF([]string{"app.example.org"}, http.NotFoundHandler()); err == nil {
+		t.Fatal("an origin without a scheme must be refused at boot, not at request time")
+	}
+}
diff --git a/platform/internal/auth/middleware.go b/platform/internal/auth/middleware.go
new file mode 100644
index 00000000..4727b644
--- /dev/null
+++ b/platform/internal/auth/middleware.go
@@ -0,0 +1,74 @@
+package auth
+
+import (
+	"net/http"
+	"strings"
+	"time"
+)
+
+// Authenticator turns a presented token into a principal. It is the ONLY place a principal is
+// created, which is what keeps the API portable to the desktop client: no endpoint can grow a
+// dependency on cookies if no endpoint ever sees one.
+type Authenticator struct {
+	Sessions SessionStore
+	IdleTTL  time.Duration
+	// Now is injectable so expiry is testable without sleeping.
+	Now func() time.Time
+	// Deny writes the 401 body. Injected because the error shape belongs to the API layer
+	// (problem+json), and auth must not depend on it.
+	Deny http.Handler
+}
+
+// Require rejects anything that does not carry a live session.
+func (a *Authenticator) Require(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		token, via, ok := present(r)
+		// No store means no session can be proven, which is a denial and not a crash: the service
+		// is allowed to run without a database (readiness says so), and a caller who presents a
+		// token must get the same 401 as a caller who presents none.
+		if !ok || a.Sessions == nil {
+			a.Deny.ServeHTTP(w, r)
+			return
+		}
+		now := a.now()
+		digest := Digest(token)
+		s, err := a.Sessions.Lookup(r.Context(), digest, now)
+		if err != nil {
+			// A store failure denies exactly like an unknown token: an authenticated caller is
+			// what a store failure cannot prove, and a distinguishable answer is an oracle.
+			a.Deny.ServeHTTP(w, r)
+			return
+		}
+		// Slide the idle window only in its second half. Sliding on every request would turn every
+		// read into a write, and the session table is on the hot path of every call.
+		if a.IdleTTL > 0 && s.IdleExpiresAt.Sub(now) < a.IdleTTL/2 {
+			_ = a.Sessions.Touch(r.Context(), digest, now, a.IdleTTL)
+		}
+		ctx := withPrincipal(r.Context(), Principal{UserID: s.UserID, Via: via})
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+func (a *Authenticator) now() time.Time {
+	if a.Now != nil {
+		return a.Now()
+	}
+	return time.Now()
+}
+
+// present extracts the token. Bearer wins over the cookie when both arrive: an explicit credential
+// beats an ambient one, and it keeps a stray cookie from deciding the CSRF path for an API client.
+func present(r *http.Request) (token string, via Presentation, ok bool) {
+	if h := r.Header.Get("Authorization"); h != "" {
+		scheme, value, found := strings.Cut(h, " ")
+		if !found || !strings.EqualFold(scheme, "Bearer") || value == "" {
+			return "", "", false
+		}
+		return value, ViaBearer, true
+	}
+	c, err := r.Cookie(CookieName)
+	if err != nil || c.Value == "" {
+		return "", "", false
+	}
+	return c.Value, ViaCookie, true
+}
diff --git a/platform/internal/auth/middleware_test.go b/platform/internal/auth/middleware_test.go
new file mode 100644
index 00000000..18c62e21
--- /dev/null
+++ b/platform/internal/auth/middleware_test.go
@@ -0,0 +1,183 @@
+package auth
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+)
+
+type fakeStore struct {
+	session  Session
+	err      error
+	lookups  int
+	digest   []byte
+	touched  int
+	touchTTL time.Duration
+}
+
+func (f *fakeStore) Lookup(_ context.Context, digest []byte, _ time.Time) (Session, error) {
+	f.lookups++
+	f.digest = digest
+	return f.session, f.err
+}
+
+func (f *fakeStore) Touch(_ context.Context, _ []byte, _ time.Time, ttl time.Duration) error {
+	f.touched++
+	f.touchTTL = ttl
+	return nil
+}
+
+func newAuth(store SessionStore, now time.Time) (*Authenticator, *int) {
+	denied := 0
+	return &Authenticator{
+		Sessions: store,
+		IdleTTL:  time.Hour,
+		Now:      func() time.Time { return now },
+		Deny: http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			denied++
+			w.WriteHeader(http.StatusUnauthorized)
+		}),
+	}, &denied
+}
+
+func TestBothPresentationsYieldAPrincipal(t *testing.T) {
+	now := time.Now()
+	token := NewToken()
+	for name, arm := range map[string]struct {
+		set func(*http.Request)
+		via Presentation
+	}{
+		"cookie": {func(r *http.Request) { r.AddCookie(&http.Cookie{Name: CookieName, Value: token}) }, ViaCookie},
+		"bearer": {func(r *http.Request) { r.Header.Set("Authorization", "Bearer "+token) }, ViaBearer},
+	} {
+		t.Run(name, func(t *testing.T) {
+			store := &fakeStore{session: Session{
+				UserID:            "u1",
+				IdleExpiresAt:     now.Add(time.Hour),
+				AbsoluteExpiresAt: now.Add(24 * time.Hour),
+			}}
+			a, denied := newAuth(store, now)
+			var seen Principal
+			h := a.Require(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+				seen, _ = FromContext(r.Context())
+			}))
+			r := httptest.NewRequest(http.MethodGet, "/v0/books", nil)
+			arm.set(r)
+			h.ServeHTTP(httptest.NewRecorder(), r)
+
+			if *denied != 0 {
+				t.Fatalf("denied a live session")
+			}
+			if seen.UserID != "u1" || seen.Via != arm.via {
+				t.Fatalf("principal = %+v", seen)
+			}
+			// What reaches the store is the digest, never the token itself.
+			if string(store.digest) == token {
+				t.Fatal("plaintext token reached the store")
+			}
+		})
+	}
+}
+
+func TestNoOrBrokenCredentialIsDenied(t *testing.T) {
+	now := time.Now()
+	for name, set := range map[string]func(*http.Request){
+		"nothing":       func(*http.Request) {},
+		"empty cookie":  func(r *http.Request) { r.AddCookie(&http.Cookie{Name: CookieName, Value: ""}) },
+		"wrong scheme":  func(r *http.Request) { r.Header.Set("Authorization", "Basic abc") },
+		"bearer empty":  func(r *http.Request) { r.Header.Set("Authorization", "Bearer ") },
+		"other cookie":  func(r *http.Request) { r.AddCookie(&http.Cookie{Name: "tm_session", Value: "x"}) },
+		"store failure": func(r *http.Request) { r.Header.Set("Authorization", "Bearer t") },
+	} {
+		t.Run(name, func(t *testing.T) {
+			store := &fakeStore{err: ErrNoSession}
+			a, denied := newAuth(store, now)
+			reached := false
+			h := a.Require(http.HandlerFunc(func(http.ResponseWriter, *http.Request) { reached = true }))
+			r := httptest.NewRequest(http.MethodGet, "/v0/books", nil)
+			set(r)
+			h.ServeHTTP(httptest.NewRecorder(), r)
+			if reached {
+				t.Fatal("handler ran without a live session")
+			}
+			if *denied != 1 {
+				t.Fatalf("deny count = %d", *denied)
+			}
+		})
+	}
+}
+
+// Found by running the binary without a database: a presented token used to reach a nil store and
+// panic into a 500. Nothing can be proven without a store, so it must deny like any other miss.
+func TestNoStoreDeniesInsteadOfPanicking(t *testing.T) {
+	a, denied := newAuth(nil, time.Now())
+	h := a.Require(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {
+		t.Fatal("handler ran with no session store")
+	}))
+	r := httptest.NewRequest(http.MethodGet, "/v0/books", nil)
+	r.Header.Set("Authorization", "Bearer t")
+	h.ServeHTTP(httptest.NewRecorder(), r)
+	if *denied != 1 {
+		t.Fatalf("deny count = %d", *denied)
+	}
+}
+
+func TestBearerWinsOverCookie(t *testing.T) {
+	r := httptest.NewRequest(http.MethodGet, "/v0/books", nil)
+	r.AddCookie(&http.Cookie{Name: CookieName, Value: "cookie-token"})
+	r.Header.Set("Authorization", "Bearer bearer-token")
+	token, via, ok := present(r)
+	if !ok || token != "bearer-token" || via != ViaBearer {
+		t.Fatalf("present() = %q %q %v", token, via, ok)
+	}
+}
+
+func TestIdleWindowSlidesOnlyInItsSecondHalf(t *testing.T) {
+	now := time.Now()
+	for name, tc := range map[string]struct {
+		remaining time.Duration
+		want      int
+	}{
+		"fresh": {50 * time.Minute, 0},
+		"stale": {10 * time.Minute, 1},
+	} {
+		t.Run(name, func(t *testing.T) {
+			store := &fakeStore{session: Session{
+				UserID:            "u1",
+				IdleExpiresAt:     now.Add(tc.remaining),
+				AbsoluteExpiresAt: now.Add(24 * time.Hour),
+			}}
+			a, _ := newAuth(store, now)
+			h := a.Require(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {}))
+			r := httptest.NewRequest(http.MethodGet, "/v0/books", nil)
+			r.Header.Set("Authorization", "Bearer t")
+			h.ServeHTTP(httptest.NewRecorder(), r)
+			if store.touched != tc.want {
+				t.Fatalf("touches = %d, want %d", store.touched, tc.want)
+			}
+		})
+	}
+}
+
+func TestTokensAreUniqueAndDigestIsStable(t *testing.T) {
+	seen := make(map[string]bool, 64)
+	for range 64 {
+		tok := NewToken()
+		if len(tok) < 40 { // 32 bytes base64url ≈ 43 chars
+			t.Fatalf("token too short: %q", tok)
+		}
+		if seen[tok] {
+			t.Fatal("token repeated")
+		}
+		seen[tok] = true
+		d := Digest(tok)
+		if len(d) != 32 {
+			t.Fatalf("digest is %d bytes", len(d))
+		}
+		if string(d) == tok {
+			t.Fatal("the stored form is the token itself")
+		}
+	}
+}
diff --git a/platform/internal/auth/principal.go b/platform/internal/auth/principal.go
new file mode 100644
index 00000000..00b88cc0
--- /dev/null
+++ b/platform/internal/auth/principal.go
@@ -0,0 +1,32 @@
+package auth
+
+import "context"
+
+// Presentation is HOW the session was presented. It exists for the CSRF layer and for logs, never
+// for authorization: a session is a session whichever way it arrived.
+type Presentation string
+
+const (
+	ViaCookie Presentation = "cookie"
+	ViaBearer Presentation = "bearer"
+)
+
+// Principal is the authenticated caller.
+type Principal struct {
+	UserID string
+	Via    Presentation
+}
+
+type principalKey struct{}
+
+// withPrincipal is deliberately unexported: the principal is created in the middleware of this
+// package and nowhere else (D39.84). A handler that could mint one could also invent a user.
+func withPrincipal(ctx context.Context, p Principal) context.Context {
+	return context.WithValue(ctx, principalKey{}, p)
+}
+
+// FromContext returns the principal established by Authenticator.
+func FromContext(ctx context.Context) (Principal, bool) {
+	p, ok := ctx.Value(principalKey{}).(Principal)
+	return p, ok
+}
diff --git a/platform/internal/auth/session.go b/platform/internal/auth/session.go
new file mode 100644
index 00000000..ece4937a
--- /dev/null
+++ b/platform/internal/auth/session.go
@@ -0,0 +1,60 @@
+// Package auth is the session layer: ONE server-side session (D39.84), presented either as a
+// __Host cookie by the browser or as a Bearer token by the desktop and CLI clients. No handler may
+// look at either — the principal is created in middleware and read from the request context.
+package auth
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"time"
+)
+
+// CookieName is the browser presentation. The __Host prefix is not decoration: it forbids a Domain
+// attribute and requires Secure + Path=/, which is what stops a sibling subdomain from writing a
+// session cookie for the app.
+const CookieName = "__Host-tm_session"
+
+// tokenBytes is 256 bits of entropy (STACK_DECISIONS §5). Opaque: it encodes nothing, so a stolen
+// token cannot be read, and a JWT's "verify without the database" property is exactly what we do
+// not want — revocation must be immediate.
+const tokenBytes = 32
+
+// ErrNoSession is returned when nothing live matches the presented token. Callers must not
+// distinguish "unknown token" from "expired token" on the wire: the difference is an oracle.
+var ErrNoSession = errors.New("auth: no live session")
+
+// Session is what the store knows about a live session.
+type Session struct {
+	UserID            string
+	IdleExpiresAt     time.Time
+	AbsoluteExpiresAt time.Time
+}
+
+// SessionStore is the persistence the middleware needs. Lookup MUST apply expiry and revocation
+// itself, so a store that forgets a clause cannot be papered over here.
+type SessionStore interface {
+	Lookup(ctx context.Context, digest []byte, now time.Time) (Session, error)
+	Touch(ctx context.Context, digest []byte, now time.Time, idleTTL time.Duration) error
+}
+
+// NewToken mints a credential. The plaintext exists only in this return value and in the client:
+// what reaches the database is Digest(token).
+//
+// No error return: crypto/rand.Read "never returns an error, and always fills b entirely" — it
+// crashes the program instead. An error path here would be dead code pretending to be a check.
+func NewToken() string {
+	b := make([]byte, tokenBytes)
+	rand.Read(b)
+	return base64.RawURLEncoding.EncodeToString(b)
+}
+
+// Digest is the stored form. Plain SHA-256 with no salt or stretching is correct HERE and only
+// here: the input is 256 uniform random bits, so there is no guessable space to slow an attacker
+// down in — unlike a password.
+func Digest(token string) []byte {
+	sum := sha256.Sum256([]byte(token))
+	return sum[:]
+}
diff --git a/platform/internal/config/config.go b/platform/internal/config/config.go
new file mode 100644
index 00000000..d65f804e
--- /dev/null
+++ b/platform/internal/config/config.go
@@ -0,0 +1,81 @@
+// Package config reads the service's settings from the environment.
+package config
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"time"
+)
+
+// Config is the whole configuration surface. Environment only: a control plane is deployed, not
+// hand-run, and a settings file is one more thing to keep in sync with the deployment.
+type Config struct {
+	Addr string
+	// DSN is the Postgres connection string. Empty is allowed and means "start unready": the
+	// service answers liveness and reports on /readyz why it cannot serve.
+	//
+	// ⚠ It carries a password. It is read from the environment, never logged, and never echoed
+	// into an error message.
+	DSN string
+	// TrustedOrigins are origins besides our own that may make unsafe requests.
+	TrustedOrigins []string
+	// SessionIdleTTL is how long a session survives without use; SessionMaxAge is the ceiling no
+	// amount of use can extend.
+	SessionIdleTTL time.Duration
+	SessionMaxAge  time.Duration
+	// Migrate applies pending migrations at boot. Off by default: a rollout should migrate once,
+	// deliberately, not once per replica.
+	Migrate bool
+}
+
+// Load reads the environment.
+func Load() (Config, error) {
+	c := Config{
+		Addr:           env("TM_PLATFORM_ADDR", "127.0.0.1:8080"),
+		DSN:            os.Getenv("TM_PLATFORM_DSN"),
+		SessionIdleTTL: 14 * 24 * time.Hour,
+		SessionMaxAge:  90 * 24 * time.Hour,
+		Migrate:        os.Getenv("TM_PLATFORM_MIGRATE") == "1",
+	}
+	if raw := os.Getenv("TM_PLATFORM_TRUSTED_ORIGINS"); raw != "" {
+		for _, o := range strings.Split(raw, ",") {
+			if o = strings.TrimSpace(o); o != "" {
+				c.TrustedOrigins = append(c.TrustedOrigins, o)
+			}
+		}
+	}
+	var err error
+	if c.SessionIdleTTL, err = duration("TM_PLATFORM_SESSION_IDLE", c.SessionIdleTTL); err != nil {
+		return Config{}, err
+	}
+	if c.SessionMaxAge, err = duration("TM_PLATFORM_SESSION_MAX_AGE", c.SessionMaxAge); err != nil {
+		return Config{}, err
+	}
+	if c.SessionIdleTTL > c.SessionMaxAge {
+		return Config{}, fmt.Errorf("config: session idle TTL %s exceeds max age %s", c.SessionIdleTTL, c.SessionMaxAge)
+	}
+	return c, nil
+}
+
+func env(key, def string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return def
+}
+
+func duration(key string, def time.Duration) (time.Duration, error) {
+	raw := os.Getenv(key)
+	if raw == "" {
+		return def, nil
+	}
+	d, err := time.ParseDuration(raw)
+	if err != nil {
+		return 0, fmt.Errorf("config: %s: %w", key, err)
+	}
+	if d <= 0 {
+		return 0, fmt.Errorf("config: %s must be positive", key)
+	}
+	return d, nil
+}
diff --git a/platform/internal/config/config_test.go b/platform/internal/config/config_test.go
new file mode 100644
index 00000000..50334677
--- /dev/null
+++ b/platform/internal/config/config_test.go
@@ -0,0 +1,48 @@
+package config
+
+import (
+	"testing"
+	"time"
+)
+
+func TestDefaultsAndOverrides(t *testing.T) {
+	c, err := Load()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.Addr != "127.0.0.1:8080" {
+		t.Fatalf("default addr = %q; a control plane must not bind the world by default", c.Addr)
+	}
+	if c.Migrate {
+		t.Fatal("migrations must be opt-in")
+	}
+
+	t.Setenv("TM_PLATFORM_ADDR", ":9000")
+	t.Setenv("TM_PLATFORM_SESSION_IDLE", "30m")
+	t.Setenv("TM_PLATFORM_TRUSTED_ORIGINS", "https://app.example.org, https://desktop.example.org ")
+	c, err = Load()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.Addr != ":9000" || c.SessionIdleTTL != 30*time.Minute {
+		t.Fatalf("config = %+v", c)
+	}
+	if len(c.TrustedOrigins) != 2 || c.TrustedOrigins[1] != "https://desktop.example.org" {
+		t.Fatalf("origins = %q", c.TrustedOrigins)
+	}
+}
+
+func TestImpossibleSessionWindowIsRefusedAtBoot(t *testing.T) {
+	t.Setenv("TM_PLATFORM_SESSION_IDLE", "100h")
+	t.Setenv("TM_PLATFORM_SESSION_MAX_AGE", "1h")
+	if _, err := Load(); err == nil {
+		t.Fatal("an idle window longer than the absolute one must fail at boot, not at 3am")
+	}
+}
+
+func TestMalformedDurationIsRefused(t *testing.T) {
+	t.Setenv("TM_PLATFORM_SESSION_IDLE", "fortnight")
+	if _, err := Load(); err == nil {
+		t.Fatal("want a parse error")
+	}
+}
diff --git a/platform/internal/httpapi/middleware.go b/platform/internal/httpapi/middleware.go
new file mode 100644
index 00000000..caab662a
--- /dev/null
+++ b/platform/internal/httpapi/middleware.go
@@ -0,0 +1,106 @@
+package httpapi
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base32"
+	"log/slog"
+	"net/http"
+	"time"
+)
+
+type requestIDKey struct{}
+
+// RequestID stamps every request. The id is ours, never the client's: an id echoed from a header
+// lets a caller poison our logs and correlate other users' lines.
+func RequestID(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var b [10]byte
+		// crypto/rand.Read never returns an error; it crashes the program instead.
+		rand.Read(b[:])
+		id := base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(b[:])
+		w.Header().Set("X-Request-Id", id)
+		next.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), requestIDKey{}, id)))
+	})
+}
+
+// RequestIDOf returns the id stamped by RequestID, or "".
+func RequestIDOf(ctx context.Context) string {
+	id, _ := ctx.Value(requestIDKey{}).(string)
+	return id
+}
+
+// SecurityHeaders applies the two product invariants to every response.
+//
+// PT-34: not one byte of a user's translation may reach an indexable URL — noindex is set here,
+// once, rather than per handler, because a handler added later would not know the rule.
+// Cache-Control: no-store is blanket for the same reason: the contract mandates it for responses
+// carrying translated text, and a private API has nothing worth caching in a shared cache.
+func SecurityHeaders(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		h := w.Header()
+		h.Set("X-Robots-Tag", "noindex, nofollow")
+		h.Set("Cache-Control", "no-store")
+		h.Set("X-Content-Type-Options", "nosniff")
+		h.Set("Referrer-Policy", "no-referrer")
+		next.ServeHTTP(w, r)
+	})
+}
+
+// Recover turns a panic into a 500 instead of a dropped connection.
+func Recover(log *slog.Logger) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			defer func() {
+				if v := recover(); v != nil {
+					log.ErrorContext(r.Context(), "panic in handler",
+						"panic", v, "path", r.URL.Path, "request_id", RequestIDOf(r.Context()))
+					WriteProblem(w, http.StatusInternalServerError, "Internal error", "")
+				}
+			}()
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+// AccessLog writes one INFO line per request. Deliberately absent: money (D39.84 and the norm of
+// the P0 prompt — costs do not reach INFO), request bodies and any user text.
+func AccessLog(log *slog.Logger) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			start := time.Now()
+			rec := &statusRecorder{ResponseWriter: w, status: http.StatusOK}
+			next.ServeHTTP(rec, r)
+			log.InfoContext(r.Context(), "request",
+				"method", r.Method,
+				// Pattern, not the raw path: the raw one carries book and run ids, which multiply
+				// log cardinality and identify a user's library in an operator's index. ServeMux
+				// fills Pattern in place, so it is readable here even though the mux ran inside.
+				"route", routeOf(r),
+				"status", rec.status,
+				"ms", time.Since(start).Milliseconds(),
+				"request_id", RequestIDOf(r.Context()))
+		})
+	}
+}
+
+func routeOf(r *http.Request) string {
+	if p := r.Pattern; p != "" {
+		return p
+	}
+	return "(unmatched)"
+}
+
+// statusRecorder captures the status code. Unwrap keeps http.ResponseController working through
+// the wrapper — that is how a later SSE handler will reach Flush.
+type statusRecorder struct {
+	http.ResponseWriter
+	status int
+}
+
+func (s *statusRecorder) WriteHeader(code int) {
+	s.status = code
+	s.ResponseWriter.WriteHeader(code)
+}
+
+func (s *statusRecorder) Unwrap() http.ResponseWriter { return s.ResponseWriter }
diff --git a/platform/internal/httpapi/problem.go b/platform/internal/httpapi/problem.go
new file mode 100644
index 00000000..e779dd47
--- /dev/null
+++ b/platform/internal/httpapi/problem.go
@@ -0,0 +1,35 @@
+package httpapi
+
+import (
+	"encoding/json"
+	"log/slog"
+	"net/http"
+)
+
+// Problem is an RFC 9457 error body.
+//
+// Detail NEVER carries engine text. The engine's own detail strings read like "CJK leak in the ru
+// output: 第一节" — pipeline vocabulary that must not cross this seam (contract §2.12). What goes
+// here is a product phrase or nothing.
+type Problem struct {
+	Type   string `json:"type"`
+	Title  string `json:"title"`
+	Status int    `json:"status"`
+	Detail string `json:"detail,omitempty"`
+}
+
+// WriteProblem renders an error response.
+func WriteProblem(w http.ResponseWriter, status int, title, detail string) {
+	w.Header().Set("Content-Type", "application/problem+json")
+	w.WriteHeader(status)
+	if err := json.NewEncoder(w).Encode(Problem{Type: "about:blank", Title: title, Status: status, Detail: detail}); err != nil {
+		slog.Debug("problem body not delivered", "err", err) // the client went away mid-write
+	}
+}
+
+// ProblemHandler is a static problem response, for the middleware that must be handed a denier.
+func ProblemHandler(status int, title string) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		WriteProblem(w, status, title, "")
+	})
+}
diff --git a/platform/internal/httpapi/server.go b/platform/internal/httpapi/server.go
new file mode 100644
index 00000000..9f206470
--- /dev/null
+++ b/platform/internal/httpapi/server.go
@@ -0,0 +1,88 @@
+package httpapi
+
+import (
+	"context"
+	"errors"
+	"log/slog"
+	"net/http"
+
+	"textmachine/platform/internal/auth"
+)
+
+// Prober is what readiness needs from the database.
+type Prober interface {
+	Ping(ctx context.Context) error
+}
+
+// Deps is everything the HTTP surface is built from.
+type Deps struct {
+	Log *slog.Logger
+	// DB is nil when no database is configured: the service still starts and still answers
+	// liveness, and readiness reports why it is not ready.
+	DB   Prober
+	Auth *auth.Authenticator
+	// TrustedOrigins are origins besides our own allowed to make unsafe requests.
+	TrustedOrigins []string
+	// APIPrefix is the contract's base path ("/v0"). Ops endpoints live outside it: a health check
+	// is not part of the versioned surface and must not move when the surface does.
+	APIPrefix string
+}
+
+// New builds the handler.
+//
+// Contract routes are registered on the SAME mux as the ops ones, with the version prefix written
+// into the pattern, and each is wrapped in guard(). One mux is what keeps Request.Pattern
+// meaningful all the way out to the access log — a nested mux behind http.StripPrefix hands the
+// inner handler a copy, and the pattern the copy learns never comes back.
+func New(d Deps) (http.Handler, error) {
+	if d.APIPrefix == "" {
+		d.APIPrefix = "/v0"
+	}
+	if d.Auth == nil {
+		return nil, errors.New("httpapi: no authenticator: the API subtree may not be served unguarded")
+	}
+	csrf, err := auth.CSRF(d.TrustedOrigins, ProblemHandler(http.StatusForbidden, "Cross-origin request rejected"))
+	if err != nil {
+		return nil, err
+	}
+	// Every API route goes through this. An anonymous caller therefore gets 401 before 404, which
+	// is deliberate: the shape of the surface is not public information.
+	guard := func(h http.Handler) http.Handler { return csrf(d.Auth.Require(h)) }
+
+	mux := http.NewServeMux()
+	mux.Handle("GET /healthz", http.HandlerFunc(healthz))
+	mux.Handle("GET /readyz", readyz(d.DB))
+	// The contract's routes land here (P-1), as mux.Handle("GET "+d.APIPrefix+"/books", guard(…)).
+	// Until then everything under the prefix is a guarded 404 in the shape the contract mandates.
+	mux.Handle(d.APIPrefix+"/", guard(ProblemHandler(http.StatusNotFound, "Object not found")))
+
+	// Recover sits INSIDE AccessLog: a panic converted to a 500 still produces a log line, whereas
+	// a panic unwinding past the logger produces none.
+	return RequestID(SecurityHeaders(AccessLog(d.Log)(Recover(d.Log)(mux)))), nil
+}
+
+// healthz is liveness: the process is up and serving. It touches nothing, so a database outage
+// cannot make a supervisor kill a healthy process.
+func healthz(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write([]byte("ok\n"))
+}
+
+// readyz is readiness: this instance can serve traffic, which means the database answers.
+func readyz(db Prober) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if db == nil {
+			WriteProblem(w, http.StatusServiceUnavailable, "Not ready", "no database configured")
+			return
+		}
+		if err := db.Ping(r.Context()); err != nil {
+			// The reason stays in the log; the body says only that we are not ready.
+			WriteProblem(w, http.StatusServiceUnavailable, "Not ready", "database unreachable")
+			return
+		}
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("ready\n"))
+	})
+}
diff --git a/platform/internal/httpapi/server_test.go b/platform/internal/httpapi/server_test.go
new file mode 100644
index 00000000..4da20a1e
--- /dev/null
+++ b/platform/internal/httpapi/server_test.go
@@ -0,0 +1,165 @@
+package httpapi
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"log/slog"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"textmachine/platform/internal/auth"
+)
+
+type prober struct{ err error }
+
+func (p prober) Ping(context.Context) error { return p.err }
+
+type liveSessions struct{}
+
+func (liveSessions) Lookup(context.Context, []byte, time.Time) (auth.Session, error) {
+	return auth.Session{UserID: "u1", IdleExpiresAt: time.Now().Add(time.Hour), AbsoluteExpiresAt: time.Now().Add(time.Hour)}, nil
+}
+func (liveSessions) Touch(context.Context, []byte, time.Time, time.Duration) error { return nil }
+
+type deadSessions struct{}
+
+func (deadSessions) Lookup(context.Context, []byte, time.Time) (auth.Session, error) {
+	return auth.Session{}, auth.ErrNoSession
+}
+func (deadSessions) Touch(context.Context, []byte, time.Time, time.Duration) error { return nil }
+
+func newServer(t *testing.T, db Prober, sessions auth.SessionStore) (http.Handler, *bytes.Buffer) {
+	t.Helper()
+	var logs bytes.Buffer
+	h, err := New(Deps{
+		Log: slog.New(slog.NewJSONHandler(&logs, nil)),
+		DB:  db,
+		Auth: &auth.Authenticator{
+			Sessions: sessions,
+			IdleTTL:  time.Hour,
+			Deny:     ProblemHandler(http.StatusUnauthorized, "Session missing or invalid"),
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return h, &logs
+}
+
+func TestHealthzIsIndependentOfTheDatabase(t *testing.T) {
+	h, _ := newServer(t, prober{err: errors.New("down")}, deadSessions{})
+	w := httptest.NewRecorder()
+	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/healthz", nil))
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d", w.Code)
+	}
+	// PT-34 and the no-store rule are applied to every response, not per handler.
+	if got := w.Header().Get("X-Robots-Tag"); !strings.Contains(got, "noindex") {
+		t.Fatalf("X-Robots-Tag = %q", got)
+	}
+	if got := w.Header().Get("Cache-Control"); got != "no-store" {
+		t.Fatalf("Cache-Control = %q", got)
+	}
+	if w.Header().Get("X-Request-Id") == "" {
+		t.Fatal("no request id")
+	}
+}
+
+func TestReadyzFollowsTheDatabase(t *testing.T) {
+	for name, tc := range map[string]struct {
+		db   Prober
+		want int
+	}{
+		"healthy":        {prober{}, http.StatusOK},
+		"unreachable":    {prober{err: errors.New("down")}, http.StatusServiceUnavailable},
+		"not configured": {nil, http.StatusServiceUnavailable},
+	} {
+		t.Run(name, func(t *testing.T) {
+			h, _ := newServer(t, tc.db, deadSessions{})
+			w := httptest.NewRecorder()
+			h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/readyz", nil))
+			if w.Code != tc.want {
+				t.Fatalf("status = %d, want %d", w.Code, tc.want)
+			}
+		})
+	}
+}
+
+func TestAPISubtreeIsGuardedBeforeItIsRouted(t *testing.T) {
+	h, logs := newServer(t, prober{}, deadSessions{})
+	w := httptest.NewRecorder()
+	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/v0/books", nil))
+	if w.Code != http.StatusUnauthorized {
+		t.Fatalf("status = %d, want 401: an anonymous caller must not be able to map the surface", w.Code)
+	}
+	assertProblem(t, w, http.StatusUnauthorized)
+	// A rejected request must still be logged: an invisible 401 is an invisible brute force.
+	if !strings.Contains(logs.String(), `"status":401`) {
+		t.Fatalf("denial not logged: %s", logs.String())
+	}
+}
+
+func TestAuthenticatedUnknownRouteIs404Problem(t *testing.T) {
+	h, _ := newServer(t, prober{}, liveSessions{})
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest(http.MethodGet, "/v0/nothing-here", nil)
+	r.Header.Set("Authorization", "Bearer t")
+	h.ServeHTTP(w, r)
+	if w.Code != http.StatusNotFound {
+		t.Fatalf("status = %d", w.Code)
+	}
+	assertProblem(t, w, http.StatusNotFound)
+}
+
+func TestAccessLogNamesTheRouteNotThePath(t *testing.T) {
+	h, logs := newServer(t, prober{}, deadSessions{})
+	h.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest(http.MethodGet, "/healthz", nil))
+	var line map[string]any
+	if err := json.Unmarshal(bytes.TrimSpace(logs.Bytes()), &line); err != nil {
+		t.Fatalf("log line: %v (%q)", err, logs.String())
+	}
+	if line["route"] != "GET /healthz" {
+		t.Fatalf("route = %v; the pattern is what keeps ids out of the log", line["route"])
+	}
+	if line["status"] != float64(http.StatusOK) {
+		t.Fatalf("status = %v", line["status"])
+	}
+}
+
+func TestPanicBecomesAProblem(t *testing.T) {
+	var logs bytes.Buffer
+	inner := http.HandlerFunc(func(http.ResponseWriter, *http.Request) { panic("boom") })
+	h := Recover(slog.New(slog.NewJSONHandler(&logs, nil)))(inner)
+	w := httptest.NewRecorder()
+	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/v0/books", nil))
+	assertProblem(t, w, http.StatusInternalServerError)
+}
+
+func TestServerRefusesToBuildWithoutAnAuthenticator(t *testing.T) {
+	if _, err := New(Deps{Log: slog.Default()}); err == nil {
+		t.Fatal("the API subtree may not be mounted unguarded")
+	}
+}
+
+func assertProblem(t *testing.T, w *httptest.ResponseRecorder, status int) {
+	t.Helper()
+	if got := w.Header().Get("Content-Type"); got != "application/problem+json" {
+		t.Fatalf("content-type = %q", got)
+	}
+	var p Problem
+	if err := json.Unmarshal(w.Body.Bytes(), &p); err != nil {
+		t.Fatalf("body: %v (%q)", err, w.Body.String())
+	}
+	if p.Status != status || p.Title == "" {
+		t.Fatalf("problem = %+v", p)
+	}
+	// Engine vocabulary must never reach a client (contract §2.12).
+	if strings.Contains(p.Detail, "sqlite") || strings.Contains(p.Detail, "pgx") {
+		t.Fatalf("internals leaked into detail: %q", p.Detail)
+	}
+}
diff --git a/platform/internal/ingest/decoder.go b/platform/internal/ingest/decoder.go
new file mode 100644
index 00000000..e496c662
--- /dev/null
+++ b/platform/internal/ingest/decoder.go
@@ -0,0 +1,103 @@
+package ingest
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+)
+
+var (
+	// ErrUnsupportedVersion is a major-version refusal: materializing a stream whose meaning
+	// changed is worse than not materializing it.
+	ErrUnsupportedVersion = errors.New("ingest: unsupported stream version")
+	// ErrNoHandshake is a stream whose first line is not the handshake. Ad-hoc unversioned JSON is
+	// the documented rot path (docker jsonmessage) and is refused at the door.
+	ErrNoHandshake = errors.New("ingest: stream does not open with hello")
+	// ErrStreamGap is a seq that skipped or went backwards: lines were lost. Recovery is not
+	// guesswork — the caller reconciles from `tmctl status --json`, the ratified resync channel.
+	ErrStreamGap = errors.New("ingest: sequence gap")
+)
+
+// maxLine caps one event. Events carry counters and ids, never text — the translated text travels
+// as artifacts — so a megabyte line means the stream is not what we think it is.
+const maxLine = 1 << 20
+
+// Decoder reads the NDJSON event stream.
+type Decoder struct {
+	sc      *bufio.Scanner
+	hello   Hello
+	greeted bool
+	lastSeq int64
+}
+
+func NewDecoder(r io.Reader) *Decoder {
+	sc := bufio.NewScanner(r)
+	sc.Buffer(make([]byte, 0, 64<<10), maxLine)
+	return &Decoder{sc: sc}
+}
+
+// Hello reads and validates the handshake. It must be called before Next.
+func (d *Decoder) Hello() (Hello, error) {
+	ev, err := d.line()
+	if err != nil {
+		if errors.Is(err, io.EOF) {
+			return Hello{}, ErrNoHandshake
+		}
+		return Hello{}, err
+	}
+	if ev.Type != TypeHello {
+		return Hello{}, fmt.Errorf("%w: first line is %q", ErrNoHandshake, ev.Type)
+	}
+	var h Hello
+	if err := json.Unmarshal(ev.Data, &h); err != nil {
+		return Hello{}, fmt.Errorf("ingest: hello payload: %w", err)
+	}
+	if err := checkVersion(h.StreamVersion); err != nil {
+		return Hello{}, err
+	}
+	d.hello, d.greeted = h, true
+	d.lastSeq = ev.Seq
+	return h, nil
+}
+
+// Next returns the next event, or io.EOF at the end of the stream. An unknown event type is
+// returned as-is: tolerating it is the minor-version rule, and dropping it is the sink's decision.
+func (d *Decoder) Next() (Envelope, error) {
+	if !d.greeted {
+		return Envelope{}, ErrNoHandshake
+	}
+	ev, err := d.line()
+	if err != nil {
+		return Envelope{}, err
+	}
+	switch {
+	case ev.Seq <= d.lastSeq:
+		// A duplicate cannot happen inside one pipe, so it is a defect rather than at-least-once
+		// redelivery — and it is reported, not silently absorbed.
+		return Envelope{}, fmt.Errorf("%w: seq %d after %d", ErrStreamGap, ev.Seq, d.lastSeq)
+	case ev.Seq > d.lastSeq+1:
+		return Envelope{}, fmt.Errorf("%w: seq %d after %d", ErrStreamGap, ev.Seq, d.lastSeq)
+	}
+	d.lastSeq = ev.Seq
+	return ev, nil
+}
+
+func (d *Decoder) line() (Envelope, error) {
+	for d.sc.Scan() {
+		raw := d.sc.Bytes()
+		if len(raw) == 0 {
+			continue // a blank line is not an event
+		}
+		var ev Envelope
+		if err := json.Unmarshal(raw, &ev); err != nil {
+			return Envelope{}, fmt.Errorf("ingest: malformed line: %w", err)
+		}
+		return ev, nil
+	}
+	if err := d.sc.Err(); err != nil {
+		return Envelope{}, fmt.Errorf("ingest: read stream: %w", err)
+	}
+	return Envelope{}, io.EOF
+}
diff --git a/platform/internal/ingest/decoder_test.go b/platform/internal/ingest/decoder_test.go
new file mode 100644
index 00000000..b0fa6c7f
--- /dev/null
+++ b/platform/internal/ingest/decoder_test.go
@@ -0,0 +1,105 @@
+package ingest
+
+import (
+	"context"
+	"errors"
+	"io"
+	"strings"
+	"testing"
+)
+
+const helloLine = `{"seq":1,"type":"hello","time":"2026-08-04T10:00:00Z","data":{"stream_version":"1.0","engine_run_id":"tr_1","book_id":"gzr"}}`
+
+func TestHelloIsRequiredFirst(t *testing.T) {
+	d := NewDecoder(strings.NewReader(`{"seq":1,"type":"progress","data":{}}` + "\n"))
+	if _, err := d.Hello(); !errors.Is(err, ErrNoHandshake) {
+		t.Fatalf("want ErrNoHandshake, got %v", err)
+	}
+	if _, err := NewDecoder(strings.NewReader("")).Hello(); !errors.Is(err, ErrNoHandshake) {
+		t.Fatalf("empty stream: want ErrNoHandshake, got %v", err)
+	}
+}
+
+func TestMajorVersionRefused(t *testing.T) {
+	line := strings.Replace(helloLine, `"stream_version":"1.0"`, `"stream_version":"2.0"`, 1)
+	if _, err := NewDecoder(strings.NewReader(line)).Hello(); !errors.Is(err, ErrUnsupportedVersion) {
+		t.Fatalf("want ErrUnsupportedVersion, got %v", err)
+	}
+}
+
+func TestMinorVersionAndUnknownFieldsTolerated(t *testing.T) {
+	line := strings.Replace(helloLine, `"stream_version":"1.0"`, `"stream_version":"1.7","future":42`, 1)
+	d := NewDecoder(strings.NewReader(line + "\n" + `{"seq":2,"type":"weather","data":{"sky":"grey"}}`))
+	if _, err := d.Hello(); err != nil {
+		t.Fatalf("minor bump must be accepted: %v", err)
+	}
+	ev, err := d.Next()
+	if err != nil {
+		t.Fatalf("unknown event type must reach the sink: %v", err)
+	}
+	if ev.Type != "weather" {
+		t.Fatalf("type = %q", ev.Type)
+	}
+}
+
+func TestSequenceGapAndReplayAreReported(t *testing.T) {
+	for name, second := range map[string]string{
+		"gap":     `{"seq":5,"type":"progress","data":{}}`,
+		"replay":  `{"seq":1,"type":"progress","data":{}}`,
+		"reverse": `{"seq":0,"type":"progress","data":{}}`,
+	} {
+		t.Run(name, func(t *testing.T) {
+			d := NewDecoder(strings.NewReader(helloLine + "\n" + second))
+			if _, err := d.Hello(); err != nil {
+				t.Fatal(err)
+			}
+			if _, err := d.Next(); !errors.Is(err, ErrStreamGap) {
+				t.Fatalf("want ErrStreamGap, got %v", err)
+			}
+		})
+	}
+}
+
+func TestIngestFeedsSinkInOrder(t *testing.T) {
+	stream := helloLine + "\n" +
+		`{"seq":2,"type":"progress","data":{"draft":{"done":1,"total":10},"edit":{"done":0,"total":10}}}` + "\n" +
+		"\n" + // a blank line is not an event
+		`{"seq":3,"type":"ceiling","data":{"halted":true}}` + "\n"
+	s := &recordingSink{}
+	if err := Ingest(context.Background(), strings.NewReader(stream), s); err != nil {
+		t.Fatalf("ingest: %v", err)
+	}
+	if s.hello.EngineRunID != "tr_1" {
+		t.Fatalf("hello not bound: %+v", s.hello)
+	}
+	if got := len(s.applied); got != 2 {
+		t.Fatalf("applied %d events, want 2", got)
+	}
+	if s.applied[0].Type != TypeProgress || s.applied[1].Type != TypeCeiling {
+		t.Fatalf("order: %v", s.applied)
+	}
+}
+
+func TestIngestStopsAtMalformedLine(t *testing.T) {
+	stream := helloLine + "\n" + "{not json\n"
+	s := &recordingSink{}
+	err := Ingest(context.Background(), strings.NewReader(stream), s)
+	if err == nil || errors.Is(err, io.EOF) {
+		t.Fatalf("want a decode error, got %v", err)
+	}
+	if len(s.applied) != 0 {
+		t.Fatalf("nothing may be applied from a broken stream, got %d", len(s.applied))
+	}
+}
+
+type recordingSink struct {
+	hello   Hello
+	applied []Envelope
+}
+
+func (s *recordingSink) Begin(_ context.Context, h Hello) error { s.hello = h; return nil }
+
+func (s *recordingSink) Apply(_ context.Context, ev Envelope) error {
+	s.applied = append(s.applied, ev)
+	return nil
+}
diff --git a/platform/internal/ingest/events.go b/platform/internal/ingest/events.go
new file mode 100644
index 00000000..b0c752cf
--- /dev/null
+++ b/platform/internal/ingest/events.go
@@ -0,0 +1,141 @@
+// Package ingest is the platform side of the engine seam (D39.85): it supervises a tmctl process,
+// reads its NDJSON event stream and hands each event to a sink that materializes it into the
+// reporting database. It never opens the engine's SQLite and never parses human output.
+//
+// ⚠ The emitter does not exist yet — it is row 103 of the engine backlog. The vocabulary below is
+// therefore the platform's PROPOSAL, derived from research/23 §7 (which call sites already carry
+// the data) and from the API contract §6 (what a reader must be told). It is written as code
+// rather than prose so the engine zone can answer it with a diff.
+package ingest
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// StreamVersion is the version this decoder implements. The rule is terraform's, ratified by
+// D39.85: a MINOR bump adds fields and event types — unknown ones are ignored; a MAJOR bump is
+// refused, because a stream whose meaning changed must not be materialized as if it had not.
+const StreamVersion = "1.0"
+
+// Type is the event name. Unknown values are legal under the minor rule and are dropped by the
+// sink, not by the decoder.
+type Type string
+
+const (
+	// TypeHello is always the first line: the version handshake.
+	TypeHello Type = "hello"
+	// TypeProgress carries the per-phase counters. Per phase because a unit is done only once its
+	// edit resolved, so one end-to-end counter reads zero for the whole draft wave.
+	TypeProgress Type = "progress"
+	// TypeUnitDone is one shipped (or withheld) edit unit.
+	TypeUnitDone Type = "unit_done"
+	// TypeBankStop is the book-wide signing stop before the edit wave.
+	TypeBankStop Type = "bank_stop"
+	// TypeCeiling is the resumable halt on the spend ceiling. It carries NO figures.
+	TypeCeiling Type = "ceiling"
+	// TypeFinished is the last line of a clean stream.
+	TypeFinished Type = "finished"
+)
+
+// Envelope is one line of the stream.
+type Envelope struct {
+	// Seq is per PROCESS and starts at 1. It is the second half of the ratified idempotency key
+	// (run_id, seq) — where run_id is Hello.EngineRunID, not the platform's run: a resumed run is
+	// a new process whose seq restarts, so keying on the platform run would drop its whole stream.
+	Seq  int64           `json:"seq"`
+	Type Type            `json:"type"`
+	Time time.Time       `json:"time"`
+	Data json.RawMessage `json:"data"`
+}
+
+// Hello is the handshake payload.
+type Hello struct {
+	StreamVersion string `json:"stream_version"`
+	// EngineRunID is the id the engine mints per invocation (today: the trace id, main.go:67-70).
+	// Once the engine accepts an external trace context (row 102) the platform can supply it, and
+	// the idempotency namespace becomes ours by construction.
+	EngineRunID string `json:"engine_run_id"`
+	BookID      string `json:"book_id"`
+	// ChunkerVersion lets the platform notice that the chapter manifest it persisted was produced
+	// by a different chunker — the case that silently re-numbers chapters (row 100).
+	ChunkerVersion string `json:"chunker_version"`
+}
+
+// Counter is a phase counter, in units.
+type Counter struct {
+	Done  int `json:"done"`
+	Total int `json:"total"`
+}
+
+// Progress is the run's counters. ETASeconds mirrors what status already computes
+// (pipeline/status.go:112) — the owner asked for a visible ETA (K-5).
+type Progress struct {
+	Draft      Counter `json:"draft"`
+	Edit       Counter `json:"edit"`
+	ETASeconds int     `json:"eta_seconds,omitempty"`
+}
+
+// UnitDone is one resolved edit unit. Chapter and Unit are the engine's own numbering; mapping
+// them onto the platform's opaque ids is the materializer's job.
+//
+// Shipped and Flagged are BOTH needed and neither implies the other: a flagged unit legally ships
+// with text (sanitizer cleanup, c-lite member drop), and the pair of them is exactly the contract's
+// derivation of unit state — shipped → translated, flagged without text → withheld.
+type UnitDone struct {
+	Chapter int    `json:"chapter"`
+	Unit    int    `json:"unit"`
+	Wave    string `json:"wave"` // draft | edit
+	Shipped bool   `json:"shipped"`
+	Flagged bool   `json:"flagged"`
+	// Reason is the ENGINE's flag reason (glossary_miss, sanitizer_stripped, …). It is stored and
+	// never projected: the product phrase is applied at read time from the contract's map, so a
+	// reason this platform has never heard of still gets a neutral phrase instead of a hole.
+	Reason string `json:"reason,omitempty"`
+}
+
+// BankStop is the signing stop. The full table travels as an artifact (engine backlog row 101),
+// not through the stream: a thousand rows are not an event.
+type BankStop struct {
+	TermsProposed int `json:"terms_proposed"`
+}
+
+// Ceiling is the ceiling halt. It carries the FACT and nothing else: money never reaches the
+// platform's wire or its INFO logs (D39.84), and the stop is resumable, so it is not a failure.
+type Ceiling struct {
+	Halted bool `json:"halted"`
+}
+
+// Finished is the terminal line. Outcome mirrors the engine's exit contract so a stream that ends
+// cleanly needs no exit-code archaeology: clean | flagged | bank_stop | failed.
+type Finished struct {
+	Outcome string `json:"outcome"`
+}
+
+// checkVersion applies the semver rule to a handshake.
+func checkVersion(got string) error {
+	gotMajor, err := major(got)
+	if err != nil {
+		return err
+	}
+	wantMajor, err := major(StreamVersion)
+	if err != nil {
+		return err
+	}
+	if gotMajor != wantMajor {
+		return fmt.Errorf("%w: stream is %s, this build speaks %s", ErrUnsupportedVersion, got, StreamVersion)
+	}
+	return nil
+}
+
+func major(v string) (int, error) {
+	head, _, _ := strings.Cut(v, ".")
+	n, err := strconv.Atoi(head)
+	if err != nil {
+		return 0, fmt.Errorf("ingest: malformed stream version %q", v)
+	}
+	return n, nil
+}
diff --git a/platform/internal/ingest/resync.go b/platform/internal/ingest/resync.go
new file mode 100644
index 00000000..752fd398
--- /dev/null
+++ b/platform/internal/ingest/resync.go
@@ -0,0 +1,56 @@
+package ingest
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// StatusReport is the ALLOWLISTED subset of `tmctl status --json` (pipeline.StatusReport) that the
+// platform materializes. Everything absent here is absent on purpose: snapshot ids, drift, rebill,
+// routing, content labels and the operator's flag taxonomy are engine vocabulary that must not
+// cross the seam (contract §2.12), and unknown JSON fields are simply ignored by encoding/json.
+//
+// ⚠ One field is money, and it is here for metering only — see SpendUSD.
+//
+// ⚠ Limit worth knowing: status has no PHASE split (engine backlog row 99). A resync can therefore
+// restore the aggregate counter but not "draft N/M ∥ edit N/M"; the phase split lives only in the
+// stream until row 99 lands. A reconciled run shows the aggregate until its next progress event.
+type StatusReport struct {
+	BookID     string `json:"book_id"`
+	TotalUnits int    `json:"total_units"`
+	Done       int    `json:"done"`
+	InProgress int    `json:"in_progress"`
+	Flagged    int    `json:"flagged"`
+	Pending    int    `json:"pending"`
+	// ETASeconds is what the owner asked to show (K-5); the engine already computes it.
+	ETASeconds float64 `json:"eta_seconds"`
+	// UnsignedBankTerms backs the signing screen's "N of M decided" while a stop is standing.
+	UnsignedBankTerms int `json:"unsigned_bank_terms"`
+	// SpendUSD is the engine's committed spend. The platform meters usage from its DELTA between
+	// attempts, because the event stream deliberately carries no figures. It is stored in the
+	// usage tables and NEVER projected into an API response or an INFO log (D39.84).
+	SpendUSD float64         `json:"committed_usd"`
+	Chapters []ChapterStatus `json:"chapters"`
+}
+
+// ChapterStatus is the per-chapter passport, allowlisted the same way (no cost, no verdict ranks).
+type ChapterStatus struct {
+	Chapter         int `json:"chapter"`
+	UnitsTotal      int `json:"units_total"`
+	UnitsDone       int `json:"units_done"`
+	UnitsFlagged    int `json:"units_flagged"`
+	UnitsInProgress int `json:"units_in_progress"`
+	UnitsPending    int `json:"units_pending"`
+	// WorstFlagReason is engine vocabulary: stored, mapped to a product phrase at read time, never
+	// projected raw.
+	WorstFlagReason string `json:"worst_flag_reason"`
+}
+
+// DecodeStatus parses a status report.
+func DecodeStatus(b []byte) (StatusReport, error) {
+	var r StatusReport
+	if err := json.Unmarshal(b, &r); err != nil {
+		return StatusReport{}, fmt.Errorf("ingest: decode status: %w", err)
+	}
+	return r, nil
+}
diff --git a/platform/internal/ingest/sink.go b/platform/internal/ingest/sink.go
new file mode 100644
index 00000000..1fc9f7e7
--- /dev/null
+++ b/platform/internal/ingest/sink.go
@@ -0,0 +1,53 @@
+package ingest
+
+import (
+	"context"
+	"errors"
+	"io"
+)
+
+// Sink materializes a stream into the reporting database.
+//
+// Idempotency lives HERE and not in the reader, because the effect and the high-water mark
+// (run_attempts.last_seq) have to move in ONE transaction: an implementation that applies an event
+// and then records it has a crash window that duplicates work.
+//
+// This is a reporting database, not an event store (research/23 §3): the events are not kept.
+type Sink interface {
+	// Begin binds the stream to an attempt — the engine's run id is the idempotency namespace.
+	Begin(ctx context.Context, h Hello) error
+	// Apply materializes one event. It MUST ignore an event whose Seq is not greater than the
+	// stored high-water mark, and it MUST ignore an unknown Type.
+	Apply(ctx context.Context, ev Envelope) error
+}
+
+// Ingest reads a stream to its end, feeding a sink.
+//
+// It stops at the first error and returns it: a gap or a malformed line is not recoverable by
+// reading further — the caller reconciles from `tmctl status --json`, which is the whole reason
+// that channel is part of the ratified seam.
+func Ingest(ctx context.Context, r io.Reader, sink Sink) error {
+	d := NewDecoder(r)
+	h, err := d.Hello()
+	if err != nil {
+		return err
+	}
+	if err := sink.Begin(ctx, h); err != nil {
+		return err
+	}
+	for {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+		ev, err := d.Next()
+		if errors.Is(err, io.EOF) {
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+		if err := sink.Apply(ctx, ev); err != nil {
+			return err
+		}
+	}
+}
diff --git a/platform/internal/ingest/supervisor.go b/platform/internal/ingest/supervisor.go
new file mode 100644
index 00000000..bd22a673
--- /dev/null
+++ b/platform/internal/ingest/supervisor.go
@@ -0,0 +1,118 @@
+package ingest
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"time"
+)
+
+// Outcome is the engine's ratified exit contract (cmd/tmctl/main.go:30-52). It is read from the
+// exit code rather than from the log, and a bank stop is deliberately NOT a failure.
+type Outcome string
+
+const (
+	OutcomeClean    Outcome = "clean"     // 0
+	OutcomeFailed   Outcome = "failed"    // 1 — infra failure, and anything unrecognised
+	OutcomeFlagged  Outcome = "flagged"   // 2 — completed with flagged units
+	OutcomeBankStop Outcome = "bank_stop" // 3 — deliberate human-in-the-loop halt
+)
+
+func outcomeOf(code int) Outcome {
+	switch code {
+	case 0:
+		return OutcomeClean
+	case 2:
+		return OutcomeFlagged
+	case 3:
+		return OutcomeBankStop
+	default:
+		return OutcomeFailed
+	}
+}
+
+// stopGrace is how long the engine has to shut down after the interrupt before it is killed. The
+// engine stops gracefully on SIGINT/SIGTERM (signal.NotifyContext in tmctl's main), and it holds an
+// EXCLUSIVE lock on its project file — a SIGKILL first would leave that lock behind.
+const stopGrace = 30 * time.Second
+
+// Supervisor runs one tmctl process per attempt.
+//
+// Stream discipline (research/23 §2): stdout belongs to the event stream and to nothing else;
+// the engine's own logs are on stderr and stay there.
+type Supervisor struct {
+	// Bin is the tmctl binary. The platform never links the engine — it spawns it (D39.81).
+	Bin string
+	// Workdir is the book's project directory: book.yaml, the source and the engine's private
+	// SQLite live there. That SQLite is never opened by us (D39.85 §4).
+	Workdir string
+	// Env is the child's environment. Provider keys reach the engine through it and must never be
+	// logged; nil means the parent's environment.
+	Env []string
+	// EngineLog receives the child's stderr verbatim. It is a FILE, not our structured logger: the
+	// engine logs per-call cost estimates at INFO, and money must not enter the platform's INFO
+	// stream (D39.84). nil discards.
+	EngineLog io.Writer
+}
+
+// Run spawns the engine and ingests its stream. It returns the outcome even when the stream itself
+// failed, because "what did the process do" and "did we materialize all of it" are different
+// questions: the second one is answered by reconciling with Status.
+func (s *Supervisor) Run(ctx context.Context, sink Sink, args ...string) (Outcome, error) {
+	cmd := exec.CommandContext(ctx, s.Bin, args...)
+	cmd.Dir = s.Workdir
+	cmd.Env = s.Env
+	cmd.Stderr = s.engineLog()
+	// CommandContext kills on cancel by default; the engine needs the signal it already handles,
+	// and WaitDelay is the backstop if it ignores it.
+	cmd.Cancel = func() error { return cmd.Process.Signal(os.Interrupt) }
+	cmd.WaitDelay = stopGrace
+
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return OutcomeFailed, fmt.Errorf("ingest: stdout pipe: %w", err)
+	}
+	if err := cmd.Start(); err != nil {
+		return OutcomeFailed, fmt.Errorf("ingest: start %s: %w", s.Bin, err)
+	}
+
+	ingestErr := Ingest(ctx, stdout, sink)
+	// Drain whatever is left so the child never blocks on a full pipe while we are waiting for it.
+	_, _ = io.Copy(io.Discard, stdout)
+
+	waitErr := cmd.Wait()
+	var exitErr *exec.ExitError
+	switch {
+	case waitErr == nil:
+		return OutcomeClean, ingestErr
+	case errors.As(waitErr, &exitErr):
+		return outcomeOf(exitErr.ExitCode()), ingestErr
+	default:
+		return OutcomeFailed, errors.Join(waitErr, ingestErr)
+	}
+}
+
+// Status runs the reconciliation channel: `tmctl status --json` on a stopped or finished run. It
+// is read-only and free, but NOT free of CPU — every call re-ingests and re-chunks the source
+// (1.4-1.5 s on a 23 MB book, engine backlog row 100), so it is a repair path, not a poll.
+func (s *Supervisor) Status(ctx context.Context) (StatusReport, error) {
+	cmd := exec.CommandContext(ctx, s.Bin, "status", "--json")
+	cmd.Dir = s.Workdir
+	cmd.Env = s.Env
+	cmd.Stderr = s.engineLog()
+	out, err := cmd.Output()
+	if err != nil {
+		return StatusReport{}, fmt.Errorf("ingest: tmctl status: %w", err)
+	}
+	return DecodeStatus(out)
+}
+
+func (s *Supervisor) engineLog() io.Writer {
+	if s.EngineLog == nil {
+		return io.Discard
+	}
+	return s.EngineLog
+}
diff --git a/platform/internal/ingest/supervisor_test.go b/platform/internal/ingest/supervisor_test.go
new file mode 100644
index 00000000..6eb592b1
--- /dev/null
+++ b/platform/internal/ingest/supervisor_test.go
@@ -0,0 +1,93 @@
+package ingest
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+// fakeEngine writes a shell script that behaves like tmctl's contract: NDJSON on stdout, human log
+// on stderr, and one of the ratified exit codes. The supervision path is exercised with a real
+// process — a mocked one would prove nothing about pipes, signals or exit codes.
+func fakeEngine(t *testing.T, stdout, stderr string, code int) string {
+	t.Helper()
+	path := filepath.Join(t.TempDir(), "tmctl")
+	script := "#!/bin/sh\nprintf '%s' " + shellQuote(stdout) + "\nprintf '%s' " + shellQuote(stderr) + " >&2\nexit " + strconv.Itoa(code) + "\n"
+	if err := os.WriteFile(path, []byte(script), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	return path
+}
+
+func TestRunIngestsStreamAndMapsExitCode(t *testing.T) {
+	stream := helloLine + "\n" + `{"seq":2,"type":"bank_stop","data":{"terms_proposed":7}}` + "\n"
+	var engineLog bytes.Buffer
+	s := &Supervisor{
+		Bin:       fakeEngine(t, stream, "bank-mining: new terms await owner signature\n", 3),
+		Workdir:   t.TempDir(),
+		EngineLog: &engineLog,
+	}
+	sink := &recordingSink{}
+
+	got, err := s.Run(context.Background(), sink, "translate", "--verify-bank")
+	if err != nil {
+		t.Fatalf("run: %v", err)
+	}
+	if got != OutcomeBankStop {
+		t.Fatalf("outcome = %q, want %q (exit 3 is a deliberate halt, not a failure)", got, OutcomeBankStop)
+	}
+	if len(sink.applied) != 1 || sink.applied[0].Type != TypeBankStop {
+		t.Fatalf("stream not materialized: %+v", sink.applied)
+	}
+	// The engine's own log must land in the file, not in our structured logger: it carries money.
+	if !bytes.Contains(engineLog.Bytes(), []byte("bank-mining")) {
+		t.Fatalf("engine stderr not captured: %q", engineLog.String())
+	}
+}
+
+func TestRunReportsOutcomeEvenWhenStreamBreaks(t *testing.T) {
+	s := &Supervisor{Bin: fakeEngine(t, "not a stream\n", "", 1), Workdir: t.TempDir()}
+	got, err := s.Run(context.Background(), &recordingSink{})
+	if err == nil {
+		t.Fatal("a broken stream must be reported")
+	}
+	if got != OutcomeFailed {
+		t.Fatalf("outcome = %q, want %q", got, OutcomeFailed)
+	}
+}
+
+func TestStatusDecodesTheResyncChannel(t *testing.T) {
+	// A real `tmctl status --json` body carries money and snapshot fields; the allowlist ignores
+	// them, and this fixture keeps one of each to prove it.
+	body := `{"book_id":"gzr","snapshot_id":"a1","committed_usd":1.25,"reserved_usd":0.5,
+		"total_units":10,"done":4,"pending":6,"eta_seconds":900,"unsigned_bank_terms":3,
+		"chapters":[{"chapter":1,"units_total":2,"units_done":2,"cost_usd":0.4,"verdict":"pass"}]}`
+	s := &Supervisor{Bin: fakeEngine(t, body, "", 0), Workdir: t.TempDir()}
+	got, err := s.Status(context.Background())
+	if err != nil {
+		t.Fatalf("status: %v", err)
+	}
+	if got.BookID != "gzr" || got.Done != 4 || got.ETASeconds != 900 || got.UnsignedBankTerms != 3 {
+		t.Fatalf("status = %+v", got)
+	}
+	if got.SpendUSD != 1.25 {
+		t.Fatalf("spend must be metered from status: %v", got.SpendUSD)
+	}
+	if len(got.Chapters) != 1 || got.Chapters[0].UnitsDone != 2 {
+		t.Fatalf("chapters = %+v", got.Chapters)
+	}
+}
+
+func TestOutcomeOfCoversTheExitContract(t *testing.T) {
+	for code, want := range map[int]Outcome{0: OutcomeClean, 1: OutcomeFailed, 2: OutcomeFlagged, 3: OutcomeBankStop, 7: OutcomeFailed} {
+		if got := outcomeOf(code); got != want {
+			t.Errorf("exit %d = %q, want %q", code, got, want)
+		}
+	}
+}
+
+func shellQuote(s string) string { return "'" + strings.ReplaceAll(s, "'", `'\''`) + "'" }
diff --git a/platform/internal/pgstore/migrate.go b/platform/internal/pgstore/migrate.go
new file mode 100644
index 00000000..2c01709d
--- /dev/null
+++ b/platform/internal/pgstore/migrate.go
@@ -0,0 +1,54 @@
+// Package pgstore is the platform's Postgres access: migrations, the pool, and the queries the
+// HTTP layer needs. It is the only package that speaks SQL.
+package pgstore
+
+import (
+	"context"
+	"database/sql"
+	"embed"
+	"fmt"
+	"io/fs"
+
+	_ "github.com/jackc/pgx/v5/stdlib" // database/sql driver "pgx", used by goose only
+	"github.com/pressly/goose/v3"
+	"github.com/pressly/goose/v3/lock"
+)
+
+//go:embed migrations/*.sql
+var migrationsFS embed.FS
+
+// Migrations exposes the embedded SQL for tests that check the set without a database.
+func Migrations() fs.FS {
+	sub, err := fs.Sub(migrationsFS, "migrations")
+	if err != nil {
+		panic(err) // the path is a compile-time constant of this package
+	}
+	return sub
+}
+
+// Migrate applies every pending migration and returns when the schema is current.
+//
+// It opens its OWN database/sql handle rather than borrowing the pgx pool: goose speaks
+// database/sql, and a one-connection handle is what the session locker needs anyway. The lock is a
+// Postgres advisory lock, so two instances rolling out at once serialize instead of racing.
+func Migrate(ctx context.Context, dsn string) error {
+	db, err := sql.Open("pgx", dsn)
+	if err != nil {
+		return fmt.Errorf("pgstore: open migration handle: %w", err)
+	}
+	defer db.Close()
+	db.SetMaxOpenConns(1)
+
+	locker, err := lock.NewPostgresSessionLocker()
+	if err != nil {
+		return fmt.Errorf("pgstore: locker: %w", err)
+	}
+	p, err := goose.NewProvider(goose.DialectPostgres, db, Migrations(), goose.WithSessionLocker(locker))
+	if err != nil {
+		return fmt.Errorf("pgstore: goose provider: %w", err)
+	}
+	if _, err := p.Up(ctx); err != nil {
+		return fmt.Errorf("pgstore: migrate: %w", err)
+	}
+	return nil
+}
diff --git a/platform/internal/pgstore/migrations/00001_identity.sql b/platform/internal/pgstore/migrations/00001_identity.sql
new file mode 100644
index 00000000..759a33ef
--- /dev/null
+++ b/platform/internal/pgstore/migrations/00001_identity.sql
@@ -0,0 +1,40 @@
+-- +goose Up
+
+-- ONE server-side session, two presentations: a __Host cookie (browser) or a Bearer token
+-- (desktop/CLI). D39.84 — the principal is established in middleware only, so nothing below
+-- knows which presentation was used.
+
+create table users (
+    id         text primary key,
+    email      text not null,
+    created_at timestamptz not null default now(),
+    -- The library read spans books, so it cannot borrow a book's counter: it needs its own
+    -- monotonic scope. Revisions are compared WITHIN a scope only (K-4 proposal).
+    library_revision bigint not null default 0
+);
+
+-- Case-insensitive identity without the citext extension: an extension is a deploy-time
+-- privilege we would need on every environment for one column.
+create unique index users_email_key on users (lower(email));
+
+create table sessions (
+    -- The token itself is never stored. A leaked dump must not yield a usable credential, so the
+    -- lookup key IS the digest: 256 random bits are not brute-forcible, no salt is needed.
+    token_sha256        bytea primary key,
+    user_id             text not null references users (id) on delete cascade,
+    created_at          timestamptz not null default now(),
+    last_used_at        timestamptz not null default now(),
+    -- Two clocks: idle expiry slides on use, absolute expiry never does — a stolen token cannot
+    -- be kept alive forever by touching it.
+    idle_expires_at     timestamptz not null,
+    absolute_expires_at timestamptz not null,
+    revoked_at          timestamptz
+);
+
+create index sessions_user_idx on sessions (user_id);
+-- The expiry sweep deletes by this; expired rows are removed, not archived.
+create index sessions_absolute_expiry_idx on sessions (absolute_expires_at);
+
+-- +goose Down
+drop table sessions;
+drop table users;
diff --git a/platform/internal/pgstore/migrations/00002_readmodel.sql b/platform/internal/pgstore/migrations/00002_readmodel.sql
new file mode 100644
index 00000000..12e37d5a
--- /dev/null
+++ b/platform/internal/pgstore/migrations/00002_readmodel.sql
@@ -0,0 +1,212 @@
+-- +goose Up
+
+-- The reporting database (research/23 §3): state materialized from the engine's event stream and
+-- from `tmctl status --json`. It is NOT an event store — no history, no replay. Every table below
+-- is a projection the API reads directly.
+--
+-- Vocabularies are checked in DDL because the PLATFORM owns them: these values are produced by our
+-- own materializer, so an unknown one is a defect, not data. Engine vocabulary (stage names, flag
+-- reasons, dispositions) is deliberately absent — it never crosses this seam.
+
+create table books (
+    id              text primary key,
+    owner_id        text not null references users (id) on delete cascade,
+    title           text not null,
+    -- Codes, never names: a language name in a shared layer is pair-specific data (canon §2).
+    source_lang     text not null,
+    target_lang     text not null,
+    genre           text not null default '',
+    status          text not null check (status in (
+        'uploading', 'parsing', 'not_started', 'translating', 'awaiting_bank', 'finalizing',
+        'ready', 'stopped', 'rejected', 'failed', 'paused')),
+    chapter_count   integer not null default 0,
+    character_count bigint not null default 0,
+    note_count      integer not null default 0,
+    added_at        timestamptz not null default now(),
+    -- ONE monotonic counter per book. Every book-scoped read and every SSE frame id of that book's
+    -- run carry it, which is what makes "drop a read older than an event already applied"
+    -- decidable at all (K-4 proposal). Bumped once per materializing transaction; the rows that
+    -- transaction touched are stamped with the new value, so a delta read is `revision > $1`.
+    revision        bigint not null default 0,
+    -- The engine project directory: book.yaml, the source file and the engine's private SQLite
+    -- live here. The platform never opens that SQLite (D39.85 §4) — it only spawns tmctl with this
+    -- as the working directory.
+    workdir         text not null,
+    engine_book_id  text not null,
+    source_sha256   bytea,
+    -- The chunker version the persisted manifest was produced under. A change re-numbers chapters
+    -- (engine backlog row 100), and chapter ids must survive that: they are ours, not the engine's.
+    chunker_version text not null default ''
+);
+
+create index books_owner_idx on books (owner_id, added_at desc, id);
+
+create table runs (
+    id          text primary key,
+    book_id     text not null references books (id) on delete cascade,
+    -- The book vocabulary minus the values that describe a book without a run.
+    status      text not null check (status in (
+        'translating', 'awaiting_bank', 'finalizing', 'ready', 'stopped', 'failed', 'paused')),
+    verify_bank boolean not null,
+    started_at  timestamptz not null default now(),
+    finished_at timestamptz,
+    -- Progress is per phase because a unit is done only once its edit resolved: one end-to-end
+    -- counter reads zero for the whole draft wave (contract §2.5; engine backlog row 99).
+    draft_done  integer not null default 0,
+    draft_total integer not null default 0,
+    edit_done   integer not null default 0,
+    edit_total  integer not null default 0,
+    eta_seconds integer,
+    revision    bigint not null default 0
+);
+
+-- One live run per book. The queue serializes by book_id (P-3) and the engine holds an EXCLUSIVE
+-- lock on the project file anyway, so a second live run is a defect the database should refuse
+-- rather than a state the API has to explain.
+create unique index runs_one_live_per_book on runs (book_id) where finished_at is null;
+create index runs_book_idx on runs (book_id, started_at desc);
+
+-- One engine PROCESS per attempt. The ratified idempotency key is (run_id, seq) — where run_id is
+-- the ENGINE's per-invocation id, not the platform run id: resume spawns a new process whose seq
+-- restarts at 1, so keying on the platform run would silently drop every event of attempt 2.
+create table run_attempts (
+    id            bigint generated always as identity primary key,
+    run_id        text not null references runs (id) on delete cascade,
+    attempt_no    integer not null,
+    -- Echoed by the stream's `hello` frame (engine backlog rows 102/103). Null until the handshake
+    -- arrives: the row is created when the process is spawned, before it says anything.
+    engine_run_id text,
+    started_at    timestamptz not null default now(),
+    ended_at      timestamptz,
+    exit_code     integer,
+    -- A high-water mark instead of an event log: the reporting database materializes state, it
+    -- does not source events (research/23 §3). A duplicate line inside one stream is dropped by
+    -- seq <= last_seq, and the mark moves in the same transaction as the effect it guards.
+    last_seq      bigint not null default 0,
+    unique (run_id, attempt_no)
+);
+
+create unique index run_attempts_engine_run_idx on run_attempts (engine_run_id);
+
+create table chapters (
+    id               text primary key,
+    book_id          text not null references books (id) on delete cascade,
+    -- Displayed ordinal, NOT a key: numbering is dense, so editing the source shifts every later
+    -- chapter (chunk/chunker.go:99-105). The key is the opaque id, which the platform keeps
+    -- stable across re-chunks.
+    number           integer not null,
+    -- Empty when the book's data carries no heading: there is no hardwired "Chapter N" form
+    -- (owner, 04.08 — K-3), and a book without chapter numbers is legal.
+    heading          text not null default '',
+    units_total      integer not null default 0,
+    -- K-10 is open. Both phase counters exist so that answering it is a projection change rather
+    -- than a migration; units_done stays the aggregate the resync path can restore today.
+    units_draft_done integer not null default 0,
+    units_edit_done  integer not null default 0,
+    units_done       integer not null default 0,
+    note_count       integer not null default 0,
+    revision         bigint not null default 0,
+    unique (book_id, number)
+);
+
+create index chapters_book_order_idx on chapters (book_id, number);
+-- Delta reads on reconnect: "everything in this book newer than the revision the client holds".
+create index chapters_book_revision_idx on chapters (book_id, revision);
+
+create table units (
+    id         text primary key,
+    chapter_id text not null references chapters (id) on delete cascade,
+    ordinal    integer not null,
+    source     text not null,
+    target     text not null default '',
+    -- Derived from the PAIR, not from the verdict: a flagged unit legally ships WITH text
+    -- (contract §2.7). The two checks below ARE that derivation, so a materializer bug that
+    -- writes "translated with no text" fails here instead of reaching a reader.
+    state      text not null check (state in ('translated', 'withheld', 'pending')),
+    revision   bigint not null default 0,
+    unique (chapter_id, ordinal),
+    constraint units_translated_has_text check (state <> 'translated' or target <> ''),
+    constraint units_unshipped_is_empty check (state = 'translated' or target = '')
+);
+
+create index units_chapter_revision_idx on units (chapter_id, revision);
+
+create table notes (
+    id         text primary key,
+    book_id    text not null references books (id) on delete cascade,
+    chapter_id text references chapters (id) on delete cascade,
+    unit_id    text references units (id) on delete cascade,
+    -- The ENGINE's flag reason, stored and never projected. The product phrase and the severity
+    -- step are applied at read time from the contract's map (companion appendix A, K-6), so the
+    -- owner's wording lands as a data change with no backfill — and an unknown reason still gets
+    -- a neutral phrase instead of a hole.
+    reason     text not null,
+    created_at timestamptz not null default now(),
+    revision   bigint not null default 0
+);
+
+create index notes_book_revision_idx on notes (book_id, revision);
+create index notes_unit_idx on notes (unit_id);
+
+create table bank_terms (
+    id             text primary key,
+    book_id        text not null references books (id) on delete cascade,
+    src            text not null,
+    dst            text not null default '',
+    -- Null is legal and means "the engine did not decide": a ruby candidate that is neither a name
+    -- nor a place carries no type (membank/memseed.go:323-326). Such a row still needs signing.
+    kind           text check (kind in ('name', 'place', 'title', 'term', 'nickname')),
+    status         text not null check (status in ('auto', 'draft', 'approved')),
+    origin         text not null check (origin in ('seed', 'ruby', 'mined')),
+    sense          text not null default '',
+    since_chapter  integer not null default 0,
+    until_chapter  integer not null default 0,
+    revision       bigint not null default 0,
+    -- The engine's own uniqueness key (store/migrate.go:202). Without the window the same src
+    -- arrives as several legal rows that look like duplicates.
+    unique (book_id, src, sense, since_chapter, until_chapter)
+);
+
+create index bank_terms_book_revision_idx on bank_terms (book_id, revision);
+
+-- Signing is NOT a row edit: the pipeline replaces a book's whole glossary from its deterministic
+-- inputs each run (seeding.go:18/110), so a decision is an accumulating instruction that the
+-- worker writes into the mined-delta / mined-rejects files before resuming.
+create table bank_decisions (
+    book_id    text not null references books (id) on delete cascade,
+    term_id    text not null references bank_terms (id) on delete cascade,
+    action     text not null check (action in ('promote', 'decline')),
+    dst        text not null default '',
+    decided_at timestamptz not null default now(),
+    decided_by text not null references users (id),
+    primary key (book_id, term_id),
+    -- The contract's conditional requirement, enforced where it cannot be generated away: an
+    -- approved term with an empty rendering matches nothing yet reads as an intended one.
+    constraint bank_decisions_promote_has_dst check (action <> 'promote' or dst <> '')
+);
+
+create table exports (
+    id            text primary key,
+    book_id       text not null references books (id) on delete cascade,
+    format        text not null,
+    ready         boolean not null default false,
+    -- Storage key of the artifact. The download URL is minted per request for the owner and is
+    -- never indexable (PT-34), so it is not a column.
+    artifact      text not null default '',
+    created_at    timestamptz not null default now(),
+    ready_at      timestamptz,
+    failed_reason text not null default ''
+);
+
+create index exports_book_idx on exports (book_id, created_at desc);
+
+-- +goose Down
+drop table exports;
+drop table bank_decisions;
+drop table bank_terms;
+drop table notes;
+drop table units;
+drop table chapters;
+drop table run_attempts;
+drop table runs;
+drop table books;
diff --git a/platform/internal/pgstore/migrations/00003_usage.sql b/platform/internal/pgstore/migrations/00003_usage.sql
new file mode 100644
index 00000000..1ff3d556
--- /dev/null
+++ b/platform/internal/pgstore/migrations/00003_usage.sql
@@ -0,0 +1,24 @@
+-- +goose Up
+
+-- P-5 draft (D39.100 / PT-35). Money is METERED here and never leaves: the API projects a state
+-- and a percentage, never a sum (D39.84). Micro-USD integers, not floats — the engine's own ledger
+-- is a lower bound and we must not add rounding drift on top of it.
+--
+-- The platform meters from `tmctl status --json` (committed_usd) at attempt boundaries, because the
+-- event stream deliberately carries no figures: the ceiling event says `halted`, nothing more.
+
+create table usage_windows (
+    user_id         text not null references users (id) on delete cascade,
+    period          text not null check (period in ('day', 'week')),
+    started_at      timestamptz not null,
+    ends_at         timestamptz not null,
+    spent_micro_usd bigint not null default 0,
+    limit_micro_usd bigint not null,
+    primary key (user_id, period, started_at)
+);
+
+-- The window a user is currently inside is the only one the limits page reads.
+create index usage_windows_current_idx on usage_windows (user_id, ends_at desc);
+
+-- +goose Down
+drop table usage_windows;
diff --git a/platform/internal/pgstore/migrations_test.go b/platform/internal/pgstore/migrations_test.go
new file mode 100644
index 00000000..1ef05ba6
--- /dev/null
+++ b/platform/internal/pgstore/migrations_test.go
@@ -0,0 +1,46 @@
+package pgstore
+
+import (
+	"io/fs"
+	"regexp"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+// The migration SET is checkable without a database, and that check is worth having: a file whose
+// name does not parse is not "skipped", it silently never runs.
+func TestMigrationSetIsWellFormed(t *testing.T) {
+	names, err := fs.Glob(Migrations(), "*")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(names) == 0 {
+		t.Fatal("no migrations embedded")
+	}
+	nameRe := regexp.MustCompile(`^(\d{5})_[a-z0-9_]+\.sql$`)
+	prev := 0
+	for _, name := range names {
+		m := nameRe.FindStringSubmatch(name)
+		if m == nil {
+			t.Fatalf("%s: goose expects NNNNN_name.sql", name)
+		}
+		version, _ := strconv.Atoi(m[1])
+		if version <= prev {
+			t.Fatalf("%s: versions must ascend and never repeat (previous %05d)", name, prev)
+		}
+		prev = version
+
+		body, err := fs.ReadFile(Migrations(), name)
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, marker := range []string{"-- +goose Up", "-- +goose Down"} {
+			if !strings.Contains(string(body), marker) {
+				// A missing Down is not cosmetic: a rollout that cannot be rolled back is a
+				// one-way door, and goose reports it only when someone tries to walk back.
+				t.Fatalf("%s: missing %q", name, marker)
+			}
+		}
+	}
+}
diff --git a/platform/internal/pgstore/pg_test.go b/platform/internal/pgstore/pg_test.go
new file mode 100644
index 00000000..e26e17c5
--- /dev/null
+++ b/platform/internal/pgstore/pg_test.go
@@ -0,0 +1,206 @@
+package pgstore
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+
+	"net/url"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+
+	"textmachine/platform/internal/auth"
+)
+
+// The database-backed battery. It runs against TM_PLATFORM_TEST_DSN and skips loudly without it —
+// `make check` names the skip, because an invisible skip reads as coverage.
+//
+// Each run gets its OWN database, created and dropped here: a test that leaves rows behind passes
+// once and then lies.
+func testDB(t *testing.T) (*Store, context.Context) {
+	t.Helper()
+	admin := os.Getenv("TM_PLATFORM_TEST_DSN")
+	if admin == "" {
+		t.Skip("TM_PLATFORM_TEST_DSN not set: schema and session tests need a live Postgres")
+	}
+	ctx := t.Context()
+
+	var suffix [6]byte
+	if _, err := rand.Read(suffix[:]); err != nil {
+		t.Fatal(err)
+	}
+	name := "tm_platform_test_" + hex.EncodeToString(suffix[:])
+
+	adminConn, err := pgx.Connect(ctx, admin)
+	if err != nil {
+		t.Fatalf("connect: %v", err)
+	}
+	if _, err := adminConn.Exec(ctx, "create database "+pgx.Identifier{name}.Sanitize()); err != nil {
+		adminConn.Close(ctx)
+		t.Skipf("cannot create a scratch database (%v): grant CREATEDB or point the DSN at one", err)
+	}
+	t.Cleanup(func() {
+		dropCtx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
+		defer cancel()
+		_, _ = adminConn.Exec(dropCtx, "drop database if exists "+pgx.Identifier{name}.Sanitize()+" with (force)")
+		adminConn.Close(dropCtx)
+	})
+
+	dsn := swapDatabase(t, admin, name)
+	if err := Migrate(ctx, dsn); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	// Twice, because a rollout re-runs it on every replica.
+	if err := Migrate(ctx, dsn); err != nil {
+		t.Fatalf("second migrate must be a no-op: %v", err)
+	}
+	s, err := Open(ctx, dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(s.Close)
+	if err := s.Ping(ctx); err != nil {
+		t.Fatal(err)
+	}
+	return s, ctx
+}
+
+func swapDatabase(t *testing.T, dsn, name string) string {
+	t.Helper()
+	u, err := url.Parse(dsn)
+	if err != nil {
+		t.Fatalf("TM_PLATFORM_TEST_DSN must be a URL: %v", err)
+	}
+	u.Path = "/" + name
+	return u.String()
+}
+
+func TestSessionLifecycle(t *testing.T) {
+	s, ctx := testDB(t)
+	now := time.Now().UTC().Truncate(time.Millisecond)
+	seedUser(t, s, ctx, "u1")
+
+	token := auth.NewToken()
+	digest := auth.Digest(token)
+	if err := s.CreateSession(ctx, digest, "u1", now, time.Hour, 24*time.Hour); err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := s.Lookup(ctx, digest, now)
+	if err != nil {
+		t.Fatalf("lookup: %v", err)
+	}
+	if got.UserID != "u1" {
+		t.Fatalf("session = %+v", got)
+	}
+
+	// Expiry is a clause of the query, not a caller's duty.
+	if _, err := s.Lookup(ctx, digest, now.Add(2*time.Hour)); !errors.Is(err, auth.ErrNoSession) {
+		t.Fatalf("expired idle window: %v", err)
+	}
+	// Sliding never outlives the absolute deadline.
+	if err := s.Touch(ctx, digest, now.Add(30*time.Minute), 48*time.Hour); err != nil {
+		t.Fatal(err)
+	}
+	slid, err := s.Lookup(ctx, digest, now.Add(30*time.Minute))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if slid.IdleExpiresAt.After(slid.AbsoluteExpiresAt) {
+		t.Fatalf("idle %s outlived absolute %s", slid.IdleExpiresAt, slid.AbsoluteExpiresAt)
+	}
+
+	if err := s.RevokeSession(ctx, digest, now); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := s.Lookup(ctx, digest, now); !errors.Is(err, auth.ErrNoSession) {
+		t.Fatalf("revoked session still resolves: %v", err)
+	}
+
+	n, err := s.DeleteExpiredSessions(ctx, now.Add(72*time.Hour))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n != 1 {
+		t.Fatalf("sweep removed %d rows, want 1", n)
+	}
+}
+
+func TestUnknownTokenIsIndistinguishable(t *testing.T) {
+	s, ctx := testDB(t)
+	if _, err := s.Lookup(ctx, auth.Digest("never-issued"), time.Now()); !errors.Is(err, auth.ErrNoSession) {
+		t.Fatalf("want ErrNoSession, got %v", err)
+	}
+}
+
+// The read-model's derivation rules are DDL, so a materializer bug fails at the write instead of
+// reaching a reader. These assert the constraints actually fire.
+func TestReadModelConstraints(t *testing.T) {
+	s, ctx := testDB(t)
+	seedUser(t, s, ctx, "u1")
+	exec(t, s, ctx, `insert into books (id, owner_id, title, source_lang, target_lang, status, workdir, engine_book_id)
+	                 values ('bk1','u1','蛊真人','zh','ru','translating','/srv/books/bk1','gzr')`)
+	exec(t, s, ctx, `insert into chapters (id, book_id, number) values ('ch1','bk1',1)`)
+
+	t.Run("translated needs text", func(t *testing.T) {
+		assertViolation(t, s, ctx, "units_translated_has_text",
+			`insert into units (id, chapter_id, ordinal, source, target, state)
+			 values ('un1','ch1',1,'第一节','','translated')`)
+	})
+	t.Run("withheld carries none", func(t *testing.T) {
+		assertViolation(t, s, ctx, "units_unshipped_is_empty",
+			`insert into units (id, chapter_id, ordinal, source, target, state)
+			 values ('un2','ch1',2,'第二节','перевод','withheld')`)
+	})
+	t.Run("promote needs a rendering", func(t *testing.T) {
+		exec(t, s, ctx, `insert into bank_terms (id, book_id, src, status, origin) values ('t1','bk1','方源','draft','mined')`)
+		assertViolation(t, s, ctx, "bank_decisions_promote_has_dst",
+			`insert into bank_decisions (book_id, term_id, action, dst, decided_by) values ('bk1','t1','promote','','u1')`)
+	})
+	t.Run("kind may be absent but not invented", func(t *testing.T) {
+		// A ruby candidate that is neither a name nor a place carries no kind, and the row is still
+		// signable — the contract forbids inventing one for it.
+		exec(t, s, ctx, `insert into bank_terms (id, book_id, src, kind, status, origin) values ('t2','bk1','李',null,'draft','ruby')`)
+		assertViolation(t, s, ctx, "bank_terms_kind_check",
+			`insert into bank_terms (id, book_id, src, kind, status, origin) values ('t3','bk1','王','org','draft','ruby')`)
+	})
+	t.Run("one live run per book", func(t *testing.T) {
+		exec(t, s, ctx, `insert into runs (id, book_id, status, verify_bank) values ('r1','bk1','translating',true)`)
+		assertViolation(t, s, ctx, "runs_one_live_per_book",
+			`insert into runs (id, book_id, status, verify_bank) values ('r2','bk1','translating',false)`)
+	})
+	t.Run("the paused status exists", func(t *testing.T) {
+		// D39.100: a ceiling stop is the eleventh book status, and it is not `failed`.
+		exec(t, s, ctx, `update books set status='paused' where id='bk1'`)
+		assertViolation(t, s, ctx, "books_status_check", `update books set status='exhausted' where id='bk1'`)
+	})
+}
+
+func seedUser(t *testing.T, s *Store, ctx context.Context, id string) {
+	t.Helper()
+	exec(t, s, ctx, `insert into users (id, email) values ($1, $1 || '@example.org')`, id)
+}
+
+func exec(t *testing.T, s *Store, ctx context.Context, sql string, args ...any) {
+	t.Helper()
+	if _, err := s.pool.Exec(ctx, sql, args...); err != nil {
+		t.Fatalf("exec %s: %v", sql, err)
+	}
+}
+
+func assertViolation(t *testing.T, s *Store, ctx context.Context, constraint, sql string) {
+	t.Helper()
+	_, err := s.pool.Exec(ctx, sql)
+	var pgErr *pgconn.PgError
+	if !errors.As(err, &pgErr) {
+		t.Fatalf("want a constraint violation, got %v", err)
+	}
+	if pgErr.ConstraintName != constraint {
+		t.Fatalf("violated %q, want %q", pgErr.ConstraintName, constraint)
+	}
+}
diff --git a/platform/internal/pgstore/sessions.go b/platform/internal/pgstore/sessions.go
new file mode 100644
index 00000000..70290d75
--- /dev/null
+++ b/platform/internal/pgstore/sessions.go
@@ -0,0 +1,85 @@
+package pgstore
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+
+	"textmachine/platform/internal/auth"
+)
+
+// Lookup resolves a presented token. Expiry and revocation are clauses of THIS query, not checks a
+// caller could forget: a row that comes back is live by construction.
+func (s *Store) Lookup(ctx context.Context, digest []byte, now time.Time) (auth.Session, error) {
+	const q = `
+		select user_id, idle_expires_at, absolute_expires_at
+		  from sessions
+		 where token_sha256 = $1
+		   and revoked_at is null
+		   and idle_expires_at > $2
+		   and absolute_expires_at > $2`
+	var out auth.Session
+	err := s.pool.QueryRow(ctx, q, digest, now).
+		Scan(&out.UserID, &out.IdleExpiresAt, &out.AbsoluteExpiresAt)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return auth.Session{}, auth.ErrNoSession
+	}
+	if err != nil {
+		return auth.Session{}, fmt.Errorf("pgstore: lookup session: %w", err)
+	}
+	return out, nil
+}
+
+// Touch slides the idle window. It never moves the absolute expiry — that is the point of having
+// two clocks — and it is called only in the window's second half, so reads stay reads.
+func (s *Store) Touch(ctx context.Context, digest []byte, now time.Time, idleTTL time.Duration) error {
+	// Deadlines are computed in Go and travel as timestamps: one clock, one place, and no interval
+	// encoding to reason about.
+	const q = `
+		update sessions
+		   set last_used_at = $2,
+		       idle_expires_at = least($3::timestamptz, absolute_expires_at)
+		 where token_sha256 = $1
+		   and revoked_at is null
+		   and absolute_expires_at > $2`
+	if _, err := s.pool.Exec(ctx, q, digest, now, now.Add(idleTTL)); err != nil {
+		return fmt.Errorf("pgstore: touch session: %w", err)
+	}
+	return nil
+}
+
+// CreateSession stores a freshly minted token's digest. The plaintext never reaches this package.
+func (s *Store) CreateSession(ctx context.Context, digest []byte, userID string, now time.Time, idleTTL, maxAge time.Duration) error {
+	const q = `
+		insert into sessions (token_sha256, user_id, created_at, last_used_at, idle_expires_at, absolute_expires_at)
+		values ($1, $2, $3, $3, $4, $5)`
+	if _, err := s.pool.Exec(ctx, q, digest, userID, now, now.Add(idleTTL), now.Add(maxAge)); err != nil {
+		return fmt.Errorf("pgstore: create session: %w", err)
+	}
+	return nil
+}
+
+// RevokeSession ends one session immediately — the property an opaque server-side session has and
+// a self-verifying token does not.
+func (s *Store) RevokeSession(ctx context.Context, digest []byte, now time.Time) error {
+	const q = `update sessions set revoked_at = $2 where token_sha256 = $1 and revoked_at is null`
+	if _, err := s.pool.Exec(ctx, q, digest, now); err != nil {
+		return fmt.Errorf("pgstore: revoke session: %w", err)
+	}
+	return nil
+}
+
+// DeleteExpiredSessions is the sweep. Expired rows are deleted rather than kept: a session table is
+// not an audit log, and "who was logged in last spring" is not a question we want to be able to
+// answer from it.
+func (s *Store) DeleteExpiredSessions(ctx context.Context, now time.Time) (int64, error) {
+	const q = `delete from sessions where absolute_expires_at <= $1`
+	tag, err := s.pool.Exec(ctx, q, now)
+	if err != nil {
+		return 0, fmt.Errorf("pgstore: sweep sessions: %w", err)
+	}
+	return tag.RowsAffected(), nil
+}
diff --git a/platform/internal/pgstore/store.go b/platform/internal/pgstore/store.go
new file mode 100644
index 00000000..ac165da9
--- /dev/null
+++ b/platform/internal/pgstore/store.go
@@ -0,0 +1,37 @@
+package pgstore
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// Store is the platform's database handle.
+type Store struct {
+	pool *pgxpool.Pool
+}
+
+// Open builds the pool. It does NOT connect: pgxpool dials lazily, so a database that is down at
+// boot makes the service unready rather than dead — readiness is the gate, not the process.
+func Open(ctx context.Context, dsn string) (*Store, error) {
+	cfg, err := pgxpool.ParseConfig(dsn)
+	if err != nil {
+		return nil, fmt.Errorf("pgstore: parse dsn: %w", err)
+	}
+	pool, err := pgxpool.NewWithConfig(ctx, cfg)
+	if err != nil {
+		return nil, fmt.Errorf("pgstore: pool: %w", err)
+	}
+	return &Store{pool: pool}, nil
+}
+
+// Ping reports whether the database is reachable; it backs /readyz.
+func (s *Store) Ping(ctx context.Context) error {
+	if err := s.pool.Ping(ctx); err != nil {
+		return fmt.Errorf("pgstore: ping: %w", err)
+	}
+	return nil
+}
+
+func (s *Store) Close() { s.pool.Close() }