feat(plugin-schedule): add DB-driven plugin scheduler and xiuren scheduled push

base/plugin_common/message_plugin_interface.py

@@ -72,3 +72,34 @@ class MessagePluginInterface(PluginInterface):
             (是否已处理, 处理结果)
         """
         raise NotImplementedError("子类必须实现此方法")
+
+    # ---------------- 插件定时调度能力（可选实现） ----------------
+    def get_schedule_actions(self) -> List[Dict[str, Any]]:
+        """返回插件支持的可调度动作定义列表。
+
+        每项示例：
+        {
+          "action_key": "daily_push",
+          "name": "每日推送",
+          "description": "给目标群发送每日内容",
+          "trigger_type": "at_times",
+          "trigger_config": {"time_list": ["09:00"]},
+          "target_scope": "all_enabled_groups",
+          "target_config": {},
+          "payload": {},
+          "default_enabled": False
+        }
+        """
+        return []
+
+    async def run_scheduled_action(self, action_key: str, context: Dict[str, Any]) -> Dict[str, Any]:
+        """执行调度动作（插件可覆盖）。
+
+        Returns:
+            dict: {"success": bool, "summary": str, "detail": dict}
+        """
+        return {
+            "success": False,
+            "summary": f"插件未实现调度动作: {action_key}",
+            "detail": {"action_key": action_key},
+        }