- Added AdvisoryCanonicalizer for canonicalizing advisory identifiers.
- Created EnsureAdvisoryCanonicalKeyBackfillMigration to populate advisory_key and links in advisory_raw documents.
- Introduced FileSurfaceManifestStore for managing surface manifests with file system backing.
- Developed ISurfaceManifestReader and ISurfaceManifestWriter interfaces for reading and writing manifests.
- Implemented SurfaceManifestPathBuilder for constructing paths and URIs for surface manifests.
- Added tests for FileSurfaceManifestStore to ensure correct functionality and deterministic behavior.
- Updated documentation for new features and migration steps.
