refactor: streamline agent lifecycle management with new DB service helpers

backend/app/services/openclaw/db_service.py

@@ -0,0 +1,47 @@
+"""Shared DB-backed service base classes for OpenClaw.
+
+These helpers are intentionally small: they reduce boilerplate (session + logger) across
+OpenClaw services without adding new architectural layers.
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from sqlmodel.ext.asyncio.session import AsyncSession
+
+
+class OpenClawDBService:
+    """Base class for OpenClaw services that require an AsyncSession."""
+
+    def __init__(self, session: AsyncSession) -> None:
+        self._session = session
+        # Use the concrete subclass module for logger naming.
+        self._logger = logging.getLogger(self.__class__.__module__)
+
+    @property
+    def session(self) -> AsyncSession:
+        return self._session
+
+    @session.setter
+    def session(self, value: AsyncSession) -> None:
+        self._session = value
+
+    @property
+    def logger(self) -> logging.Logger:
+        return self._logger
+
+    @logger.setter
+    def logger(self, value: logging.Logger) -> None:
+        self._logger = value
+
+    async def add_commit_refresh(self, model: object) -> None:
+        """Persist a model, committing the current transaction and refreshing when supported."""
+
+        self.session.add(model)
+        await self.session.commit()
+        refresh = getattr(self.session, "refresh", None)
+        if callable(refresh):
+            await refresh(model)