fix(ci): resolve ruff lint errors, mypy type issues

feat: add /metrics endpoint, Supabase JWKS auth, Prometheus instrumentation

fix(security): enforce RBAC and close five denial-of-service vectors

feat: scaffold CV screener serving layer with ingestion pipeline, REST API routers, repositories, storage, parsing, security, and integration/unit test foundations

feat(api): add Phase 0-1 backend for identity and document ingestion