- Log warning if /app mount not found when sharing poll task group
- Add docstring explaining unconditional task group creation
- Check session expires_at in provision_status to catch stale sessions
- Guard _poll_and_store status writes against cleanup-while-polling race
- Use "error" status (not "expired") when app_password is missing
- Remove hardcoded "Astrolabe Background Sync" user_agent string
- Fix async mock pattern (new_callable=AsyncMock) in test
- Add autouse fixture to clear _provision_sessions between tests
- Add _poll_and_store unit tests: completed, expired, error, cleanup
- Document all status values in provision_status docstring
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
