feat: start resume sessions in new flow

backend/app/database.py

@@ -160,8 +160,13 @@ class Database:
             self.insert_turn(connection, session_id=session_id, **initial_turn)
 
     def fetch_session(
-        self, connection: sqlite3.Connection, session_id: str
+        self,
+        connection: sqlite3.Connection,
+        session_id: str,
+        *,
+        for_update: bool = False,
     ) -> dict[str, Any] | None:
+        del for_update
         row = connection.execute(
             "SELECT * FROM sessions WHERE id = ?", (session_id,)
         ).fetchone()