feat(jpa): implement the JPA relational persistence platform

Implements the Stable and Experimental JPA persistence platform designs
against real PostgreSQL, adapted to this repository's fail-closed 19-leaf
registry.

The design models the platform as 25 Gradle projects. `src/settings.gradle`
throws unless the registry holds exactly 19 leaves, so the plan's modules
become packages inside `:adapter:outbound:persistence-jpa` (starter in
`:app-bootstrap`, testkit in its own source set). The full mapping, the
renames this repository's naming gate required, and every deliberate
substitution are recorded in `docs/jpa/repository-adaptation.md`.

Seven Docker-backed lanes replace the plan's seven JVM test suites. Each
fails closed: a lane that discovers nothing, or a container that cannot
start, is an error rather than a skip.

Three defects the contracts found against a real server:

- `CommitFailureClassifier` treated only SQLSTATE 40003, class 08, and
  transport breaks as completion-unknown. A backend terminated mid-commit
  reports 57P01, and the commit record may already be in the WAL — so a
  possibly-committed transaction could be re-run. 57P01/57P02/57P03 now
  classify as completion-unknown.
- `SchemaTenantMigrationOrchestrator` recorded `MigrateResult`'s target
  version, which is empty for a tenant already current, reporting migrated
  tenants as unmigrated during a partial rollout. It now reads the applied
  version back from the tenant's schema history.
- `JpaStreamExecutor` checked only the declared return type for reactive
  publishers, and `RegisteredPostgreSqlCopyLoader` passed the COPY timeout
  to `SET`, which is parsed before parameter binding.

`JpaModuleBoundaryTest` enforces the plan's module map as package rules;
`verifyCleanArchitectureDependencies` governs edges between leaves and
cannot see these. Its first assertion is that the import is non-empty,
because every rule under it is a `noClasses()` rule and would pass
vacuously on an empty import.

Verified: 128 container tests across all seven lanes, 1183 unit tests,
`:adapter:outbound:persistence-jpa:check`, `:app-bootstrap:check`,
`verifyCleanArchitectureDependencies`, `verifyOneTypePerFile`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.github/workflows/jpa-pr.yml

@@ -0,0 +1,114 @@
+name: jpa-pr
+
+# Every "Stable" row in docs/jpa/support-matrix.md is backed by a job here or in jpa-nightly /
+# jpa-release. A support level with no job behind it is a marketing claim.
+#
+# The PR lane runs the oldest and the newest Stable PostgreSQL rather than all three: a behaviour
+# that differs across the matrix almost always differs at its ends, and the middle version is
+# covered nightly. What it does not do is skip the container lane on a runner without Docker —
+# PostgreSqlContainerFactory throws, because a skipped contract reports success for a database
+# nobody tested.
+
+on:
+  workflow_dispatch:
+  pull_request:
+    paths:
+      - 'src/adapter/outbound/persistence-jpa/**'
+      - 'src/app-bootstrap/src/**/jpa/**'
+      - 'src/config/architecture/modules.json'
+      - 'docs/jpa/**'
+      - 'docs/adr/ADR-JPA-*'
+      - 'infra/jpa/**'
+      - '.github/workflows/jpa-pr.yml'
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  jpa-unit-and-architecture:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # actions/checkout@v4.2.2
+      - name: Validate Gradle wrapper
+        id: gradle-wrapper-validation
+        uses: gradle/actions/wrapper-validation@3f131e8634966bd73d06cc69884922b02e6faf92 # gradle/actions@v6
+      - uses: actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00 # actions/setup-java@v4.7.1
+        with:
+          distribution: temurin
+          java-version: "21.0.11+10"
+          cache: gradle
+          cache-dependency-path: |
+            src/**/*.gradle
+            src/**/gradle-wrapper.properties
+            src/**/gradle.lockfile
+      - name: Run the JPA unit and architecture suites
+        working-directory: src
+        run: >-
+          ./gradlew
+          :adapter:outbound:persistence-jpa:test
+          :app-bootstrap:test --tests '*CleanArchitectureTest'
+          verifyCleanArchitectureDependencies
+          verifyOneTypePerFile
+          --no-daemon
+          --stacktrace
+
+  jpa-postgresql-contract:
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    strategy:
+      fail-fast: false
+      matrix:
+        # 16 and 18 — the ends of the Stable matrix. 17 runs nightly.
+        postgresql: ["16", "18"]
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # actions/checkout@v4.2.2
+      - name: Validate Gradle wrapper
+        id: gradle-wrapper-validation
+        uses: gradle/actions/wrapper-validation@3f131e8634966bd73d06cc69884922b02e6faf92 # gradle/actions@v6
+      - uses: actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00 # actions/setup-java@v4.7.1
+        with:
+          distribution: temurin
+          java-version: "21.0.11+10"
+          cache: gradle
+          cache-dependency-path: |
+            src/**/*.gradle
+            src/**/gradle-wrapper.properties
+            src/**/gradle.lockfile
+      - name: Certify the platform against PostgreSQL ${{ matrix.postgresql }}
+        working-directory: src
+        run: >-
+          ./gradlew
+          :adapter:outbound:persistence-jpa:jpaPlatformContractTest
+          -Pjpa.matrix.versions=${{ matrix.postgresql }}
+          --no-daemon
+          --stacktrace
+
+  jpa-migration-smoke:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # actions/checkout@v4.2.2
+      - name: Validate Gradle wrapper
+        id: gradle-wrapper-validation
+        uses: gradle/actions/wrapper-validation@3f131e8634966bd73d06cc69884922b02e6faf92 # gradle/actions@v6
+      - uses: actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00 # actions/setup-java@v4.7.1
+        with:
+          distribution: temurin
+          java-version: "21.0.11+10"
+          cache: gradle
+          cache-dependency-path: |
+            src/**/*.gradle
+            src/**/gradle-wrapper.properties
+            src/**/gradle.lockfile
+      - name: Run the migration upgrade smoke scenarios
+        working-directory: src
+        run: >-
+          ./gradlew
+          :adapter:outbound:persistence-jpa:jpaPlatformMigrationTest
+          --no-daemon
+          --stacktrace