feat(F-002): database foundation with migrations and dev compose

- node-pg-migrate + pg: baseline migration (extensions, app_meta) with working down
- src/infrastructure/db fail-fast pool and typed query helper
- docker-compose: postgres:16-alpine + redis:7-alpine with one-command up
- table naming convention <module>_<table> documented in README
- integration tests (6) against real PostgreSQL; strict identifier validation
  for test DDL after security-gate hardening round
- deps justified in spec/tech.md; all gates approved; verify.sh green

work/artifacts/F-002/leader-close.json

@@ -0,0 +1,34 @@
+{
+  "feature_id": "F-002",
+  "agent": "leader",
+  "verdict": "APPROVED",
+  "summary": "F-002 closed. Database foundation implemented and proven against real PostgreSQL 16 + Redis 7: migrations up/down/no-op, fail-fast pool, one-command dev environment, naming convention documented. All gates APPROVED, verify.sh exit 0.",
+  "gates": {
+    "reviewer": "APPROVED (reviewer.json)",
+    "security": "APPROVED (security.json, after identifier-validation hardening round)",
+    "qa": "APPROVED (qa.json)",
+    "verify_sh": "exit 0"
+  },
+  "deliverables": [
+    "project/migrations/001_baseline.js with working down migration",
+    "project/src/infrastructure/db/pool.ts (fail-fast pool + typed query helper)",
+    "project/docker-compose.yml (postgres:16-alpine + redis:7-alpine)",
+    "npm scripts: db:up/down/status, docker:up/down, test:integration",
+    "6 integration tests passing against real PostgreSQL; helper identifier validation regression-tested",
+    "specs/F-002-database-foundation complete; spec/tech.md dependency justifications"
+  ],
+  "process_notes": [
+    "Security gate bounced one low finding (DDL identifier interpolation in test support) back to build; fixed with strict validation + tests, then re-approved. The gate worked as designed."
+  ],
+  "next_feature_hint": "F-003 (HTTP foundation/request context) and F-004 (config/flags) only depend on F-001; F-005 identity now unblocked by F-002",
+  "evidence": [
+    "work/artifacts/F-002/architect.md",
+    "work/artifacts/F-002/implementer.md",
+    "work/artifacts/F-002/reviewer.json",
+    "work/artifacts/F-002/security.json",
+    "work/artifacts/F-002/qa.json",
+    "work/artifacts/F-002/documenter.md",
+    "./scripts/verify.sh exit 0 at close"
+  ],
+  "timestamp": "2026-08-14T20:04:00Z"
+}