Remove dead task DB fast-path and update task tests

backend/tests/test_tasks/test_history_sync.py

@@ -36,8 +36,10 @@ class TestHistorySyncTask:
         fake_app.state = type("FakeState", (), {})()
         fake_app.state.settings = type("FakeSettings", (), {})()
         fake_app.state.settings.fail2ban_socket = "/tmp/fake.sock"
+        fake_app.state.settings.database_path = "/tmp/fake.db"
 
         fake_app.state.db = MagicMock()
+        fake_app.state.db.close = AsyncMock()
 
         async def fake_get_history_page(*, db_path: str, since: int, page: int, page_size: int, **kwargs):
             assert since == 1001
@@ -47,6 +49,10 @@ class TestHistorySyncTask:
             return "/tmp/fake.sqlite3"
 
         with patch(
+            "app.tasks.history_sync.open_db",
+            new_callable=AsyncMock,
+            return_value=fake_app.state.db,
+        ), patch(
             "app.tasks.history_sync._get_last_archive_ts",
             new=AsyncMock(return_value=1000),
         ), patch(