Function open_test_db_with_user_and_host_blobs 

pub fn open_test_db_with_user_and_host_blobs(
    store_dir: StoreDir,
    photo_decl: BlobDecl,
    cover_decl: BlobDecl,
) -> Database

The synthetic store’s schema and Database constructors, which the database layer owns and its own tests open directly. Open a test Database with both note_photos (per photo_decl) and note_covers (per cover_decl) declared blob-bearing — the schema for the per-provenance transition tests.