- loadConfig: pure over env object, accumulates all problems, names var names only
- DATABASE_URL now required at startup; PORT/HOST/LOG_LEVEL/NODE_ENV/REDIS_URL defaulted
- flags module behind FeatureFlagProvider; unknown flags OFF; runtime setEnabled (no redeploy)
- buildApp decorates app.flags; server.ts fail-fast before app boot
- tests caught and fixed flag-store case-normalization bug before gates
- zero new dependencies; all gates approved; verify.sh green
- request_id generated or sanitized-propagated on every request (x-request-id)
- structured JSON logging (pino), one correlated line per request, injectable logger
- error envelope v2 { error: { statusCode, code, message, details? }, requestId }
- 5xx messages always generic; stack traces stay in server logs only
- explicit parseJson (zod) input validation hook at the API layer
- README HTTP contract section; deps justified in spec/tech.md
- all gates approved; verify.sh green