fix(api): support asset library lookup for media guards

packages/adapters/sqlalchemy_impl/asset_library_repository.py

@@ -8,6 +8,22 @@ class SQLAlchemyAssetLibraryRepository:
     def __init__(self, session: Session):
         self.session = session
 
+    def get(self, library_id: str) -> AssetLibrary | None:
+        model = self.session.query(AssetLibraryModel).filter(AssetLibraryModel.id == library_id).first()
+        if model is None:
+            return None
+        return AssetLibrary(
+            id=model.id,
+            workspace_id=model.workspace_id,
+            project_id=model.project_id,
+            name=model.name,
+            kind=AssetLibraryKind(model.kind),
+            asset_count=int(model.asset_count or 0),
+            total_size=int(model.total_size or 0),
+            created_at=model.created_at,
+            updated_at=model.updated_at,
+        )
+
     def list_by_project(self, project_id: str, kind: AssetLibraryKind | None = None) -> list[AssetLibrary]:
         query = self.session.query(AssetLibraryModel).filter(AssetLibraryModel.project_id == project_id)
         if kind is not None:

tests/unit/test_asset_library_repository.py

@@ -0,0 +1,33 @@
+from packages.adapters.sqlalchemy_impl.asset_library_repository import SQLAlchemyAssetLibraryRepository
+from packages.adapters.sqlalchemy_impl.models import AssetLibraryModel
+from tests.unit.test_workspace_sqlalchemy_repositories import _sqlite_session
+
+
+def test_asset_library_repository_get_returns_library():
+    session = _sqlite_session()
+    session.add(
+        AssetLibraryModel(
+            id="lib-1",
+            workspace_id="workspace-1",
+            project_id="project-1",
+            name="素材库",
+            kind="video",
+            asset_count=2,
+            total_size=10,
+        )
+    )
+    session.commit()
+
+    library = SQLAlchemyAssetLibraryRepository(session).get("lib-1")
+
+    assert library is not None
+    assert library.id == "lib-1"
+    assert library.workspace_id == "workspace-1"
+    assert library.project_id == "project-1"
+    assert library.kind.value == "video"
+
+
+def test_asset_library_repository_get_returns_none_for_missing_library():
+    session = _sqlite_session()
+
+    assert SQLAlchemyAssetLibraryRepository(session).get("missing") is None