BREAKING CHANGE: API authentication is now always required. The
PINCHFLAT_API_TOKEN env var is no longer used. Instead, tokens are
stored in the database and managed via Settings → API Access.
Changes:
- Add api_token column to settings table (migration)
- ApiAuthPlug reads from DB; returns 401 if no token configured
- Add API Access section to Settings page with generate/regenerate/revoke
- Add POST /settings/generate_api_token and /settings/revoke_api_token
- Remove api_token from config.exs and runtime.exs
- Update all API controller tests to set auth token in setup
- Update auth plug tests for mandatory authentication
- 1008 tests pass, zero warnings