将persist和后端分离，方便替换为其他数据库

tests/unit/test_scope_persistence_partitioning.py

@@ -7,6 +7,7 @@ import pytest
 from sync_state_machine.common.binding import BindingManager
 from sync_state_machine.common.collection import DataCollection
 from sync_state_machine.common.persistence import PersistenceBackend
+from sync_state_machine.common.sqlite_backend import SQLitePersistenceBackend
 from tests.fixtures.mock_domain import build_project_node, register_test_domain
 
 
@@ -15,7 +16,7 @@ async def test_scope_partitioning_and_copy_between_scopes(tmp_path: Path) -> Non
     register_test_domain()
 
     db_path = tmp_path / "scope_partitioning.db"
-    persistence = PersistenceBackend(str(db_path))
+    persistence = SQLitePersistenceBackend(str(db_path))
     await persistence.initialize()
 
     global_collection = DataCollection("local", scope="global", persistence=persistence, auto_persist=False)