Phase 3.7: paid pairing flow + returning chat + extension flip

- Backend: payment_sessions + pairing_failures tables; payment.service.js
  and pairing-failure.service.js (new); rewritten pairing.service.js
  (payment-gated blast + targeted "Curhat lagi" + cancel + fallback);
  rewritten extension.service.js (data-driven auto-approve with offline
  safeguard, charge-at-approval); pricing.service.js (extension tiers
  without free trial); mitra-status.service.js (countAvailableMitras
  cached path); 60s sweeper for stale payment sessions
- Backend routes: client.payment.routes, client.mitra-availability.routes,
  internal/failed-pairings.routes; client.chat.routes rewritten for
  payment-gated start + /returning + /cancel + /fallback-to-blast;
  internal/config.routes adds 4 new keys with Valkey invalidate publish
- client_app: mitra-availability poll, payment screen + notifier, pairing
  notifier rewrite (PairingTargetedWaiting + PairingFailed states),
  targeted-waiting overlay + bestie-unavailable dialog, "Curhat lagi"
  CTA, failed-pairing terminal, extension via payment-session
- mitra_app: PairingRequestType enum, returning-chat 20s countdown
  auto-dismiss, extension card "otomatis disetujui" copy
- control_center: 4 new config rows in Settings, Failed Pairings page
  (filter + paginate + action menu), sidebar + route registered
- Test infrastructure: Vitest backend (7/7 pass), Playwright CC (4/4
  pass), Maestro mobile scaffold (CLI install pending)
- Bugs found via Playwright + fixed: LoginPage labels not associated
  with inputs (a11y); backend internal CORS missing PATCH/PUT/DELETE
  in allow-methods (silent settings breakage in browsers since Stage 4)
- Docs: phase3.7.md PRD, phase3.7-plan.md, phase3.7-questions.md (Q&A),
  phase3.7-testing.md (E2E checklist), phase3.7-test-run-2026-05-03.md
  (today's run results)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/docker-compose.test.yml

@@ -0,0 +1,34 @@
+# Alternative test infrastructure: ephemeral Postgres + Valkey containers.
+#
+# CURRENT DEFAULT is Option C (schema-isolated remote DB) because the dev role on
+# the remote DB cannot CREATE DATABASE. Use this docker-compose if you'd rather
+# run an isolated, throwaway test DB on your local machine.
+#
+# To switch to docker-compose:
+#   1. docker compose -f docker-compose.test.yml up -d
+#   2. In .env.test set:
+#        TEST_DATABASE_URL=postgresql://test:test@localhost:55432/halobestie_test
+#        TEST_DB_SCHEMA=public
+#        TEST_VALKEY_URL=redis://localhost:56379/0
+#   3. npm test
+#   4. docker compose -f docker-compose.test.yml down -v
+#
+# The non-default ports (55432, 56379) avoid clashing with any local Postgres/Redis.
+services:
+  postgres-test:
+    image: postgres:15-alpine
+    environment:
+      POSTGRES_USER: test
+      POSTGRES_PASSWORD: test
+      POSTGRES_DB: halobestie_test
+    ports:
+      - "55432:5432"
+    tmpfs:
+      - /var/lib/postgresql/data  # ephemeral — wiped on container stop
+
+  valkey-test:
+    image: valkey/valkey:7-alpine
+    ports:
+      - "56379:6379"
+    tmpfs:
+      - /data