Validates session on app mount by calling GET /api/auth/session instead of relying
solely on cached sessionStorage. This ensures the UI state always reflects server
reality — expired or revoked sessions are detected immediately.
Changes:
- Backend: Add GET /api/auth/session endpoint (requires valid session, returns 200/401)
- Frontend: Add useSessionValidation hook for mount-time validation
- Frontend: Add SessionValidationLoading component for validation spinner
- Frontend: Update AuthProvider to call validation on mount with loading state
- Frontend: Add validateSession API function
- Docs: Update Features.md with session validation behavior
- Docs: Update Web-Development.md with session validation pattern
Handles three outcomes:
1. Valid session (200): Proceed with cached state
2. Invalid session (401): Clear sessionStorage and redirect to login
3. Network error: Don't logout (backend may be temporarily unreachable)
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- 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.
