chore(20): persistent CI caches — pnpm store + Playwright browsers

- All four pnpm install steps now use --store-dir /pnpm-store --prefer-offline
- harness job env adds PLAYWRIGHT_BROWSERS_PATH: /ms-playwright
- Updated stale D-PROBE-04 comments to reflect persistent store
- Playwright install step gets a comment noting the future runner-image optimization

.gitea/workflows/ci.yml

@@ -46,12 +46,12 @@ jobs:
       - name: Enable pnpm
         run: corepack enable pnpm
 
-      # actions/cache@v4 is intentionally omitted — probe (D-PROBE-04) showed it
-      # times out on this runner (socket hang-up between runner container and job
-      # container cache server). pnpm install without cache takes ~30s; acceptable.
+      # actions/cache@v4 intentionally omitted (D-PROBE-04). Installs now target the
+      # host-mounted pnpm store at /pnpm-store (see act_runner config.yaml container.options).
+      # Without the host mount the flag still works — pnpm creates an ephemeral store there.
 
       - name: Install dependencies
-        run: pnpm install --frozen-lockfile
+        run: pnpm install --frozen-lockfile --store-dir /pnpm-store --prefer-offline
 
       - name: Lint
         run: pnpm lint
@@ -104,10 +104,11 @@ jobs:
       - name: Enable pnpm
         run: corepack enable pnpm
 
-      # actions/cache@v4 intentionally omitted — same reasoning as fast-checks job (D-PROBE-04).
+      # actions/cache@v4 intentionally omitted (D-PROBE-04). Installs now target the
+      # host-mounted pnpm store at /pnpm-store (see act_runner config.yaml container.options).
 
       - name: Install dependencies
-        run: pnpm install --frozen-lockfile
+        run: pnpm install --frozen-lockfile --store-dir /pnpm-store --prefer-offline
 
       # Pitfall 11: service container healthy != MariaDB accepting connections.
       # No mysql CLI in the runner image (D-PROBE-03); poll via the already-installed
@@ -181,6 +182,9 @@ jobs:
       DB_USER: familysync
       DB_PASSWORD: testpass
       DB_NAME: familysync
+      # Persist Playwright browser binaries across runs via host-mounted /ms-playwright.
+      # Without the host mount CI still works — binaries are downloaded to the ephemeral dir.
+      PLAYWRIGHT_BROWSERS_PATH: /ms-playwright
     steps:
       - uses: actions/checkout@v4
 
@@ -191,10 +195,11 @@ jobs:
       - name: Enable pnpm
         run: corepack enable pnpm
 
-      # actions/cache@v4 intentionally omitted — same reasoning as fast-checks job (D-PROBE-04).
+      # actions/cache@v4 intentionally omitted (D-PROBE-04). Installs now target the
+      # host-mounted pnpm store at /pnpm-store (see act_runner config.yaml container.options).
 
       - name: Install dependencies
-        run: pnpm install --frozen-lockfile
+        run: pnpm install --frozen-lockfile --store-dir /pnpm-store --prefer-offline
 
       # Pitfall 11: service container healthy != MariaDB accepting connections.
       # No mysql CLI in the runner image (D-PROBE-03); poll via the mysql2 driver
@@ -270,7 +275,9 @@ jobs:
       # Install Playwright browsers with system deps BEFORE starting the API, so the long
       # browser download does not run during the API's lifetime.
       # Must run from apps/pwa/ where @playwright/test is installed (D-PROBE-05 confirmed exit 0).
-      # Do NOT cache browser binaries — Playwright explicitly recommends against it in CI.
+      # PLAYWRIGHT_BROWSERS_PATH=/ms-playwright (job-level env) persists binaries across runs via
+      # the host-mounted dir. The --with-deps apt step cannot be cached; baking a runner image
+      # with browsers preinstalled would also drop the --with-deps apt step (future optimization).
       - name: Install Playwright browsers
         run: npx playwright install --with-deps webkit chromium
         working-directory: apps/pwa
@@ -462,7 +469,8 @@ jobs:
             --exit-code 1
 
       # ── pnpm audit + outdated (code-change PRs only, D-12) ───────────────────
-      # actions/cache@v4 intentionally omitted — same reasoning as fast-checks job (D-PROBE-04).
+      # actions/cache@v4 intentionally omitted (D-PROBE-04). Installs now target the
+      # host-mounted pnpm store at /pnpm-store (see act_runner config.yaml container.options).
 
       - uses: actions/setup-node@v4
         if: needs.changes.outputs.code == 'true'
@@ -475,7 +483,7 @@ jobs:
 
       - name: Install dependencies
         if: needs.changes.outputs.code == 'true'
-        run: pnpm install --frozen-lockfile
+        run: pnpm install --frozen-lockfile --store-dir /pnpm-store --prefer-offline
 
       - name: Dependency audit (blocking on High+Critical)
         if: needs.changes.outputs.code == 'true'