优化加载后删除节点的逻辑；和数据库查询性能

tests/unit/test_scope_persistence_partitioning.py

@@ -55,4 +55,22 @@ async def test_scope_partitioning_and_copy_between_scopes(tmp_path: Path) -> Non
     await reloaded_global.load_from_persistence()
     assert len(reloaded_global.filter(node_type="test_project")) == 1
 
+    await persistence.close()
+
+
+@pytest.mark.asyncio
+async def test_sqlite_backend_creates_restore_join_index(tmp_path: Path) -> None:
+    db_path = tmp_path / "scope_partitioning.db"
+    persistence = SQLitePersistenceBackend(str(db_path))
+    await persistence.initialize()
+
+    columns, rows = PersistenceBackend.query_records(
+        backend="sqlite",
+        db_path=str(db_path),
+        sql="PRAGMA index_list('nodes')",
+    )
+
+    assert columns == ["seq", "name", "unique", "origin", "partial"]
+    assert any(row["name"] == "idx_nodes_scope_type_node_id" for row in rows)
+
     await persistence.close()