- Cache setup_completed flag in app.state._setup_complete_cached after
first successful is_setup_complete() call; all subsequent API requests
skip the DB query entirely (one-way transition, cleared on restart).
- Add in-memory session token TTL cache (10 s) in require_auth; the second
request with the same token within the window skips session_repo.get_session.
- Call invalidate_session_cache() on logout so revoked tokens are evicted
immediately rather than waiting for TTL expiry.
- Add clear_session_cache() for test isolation.
- 5 new tests covering the cached fast-path for both optimisations.
- 460 tests pass, 83% coverage, zero ruff/mypy warnings.
