- #627: Set source.asset (URL/file_path) before save() in async creation
path so failed sources are identifiable and retry works
- #670: Only overwrite source title if it's a placeholder ("Processing...")
or empty, preserving user-set custom titles
- #651: Cascade-delete linked models when credential is deleted instead of
returning 409 Conflict; remove unused delete_models parameter
- Add tests for all three fixes (12 new tests)
- Add .harness and .mcp.json to .gitignore
