refactor(schemas): 统一 message/notification 命名边界，旧名收敛至兼容映射表

- notification 域：渠道能力（MessageChannel→NotificationChannel、ChannelCapability* 迁入 notification.py）
- message 域：消息收发（Notification→Message、NotificationType→MessageType、CommingMessage→IncomingMessage、NotificationHistoryItem→MessageHistoryItem、NotificationClear*→MessageClear*）
- Agent 工具契约：send_notification_message→send_message、notification_callback→message_callback
- 源码不保留旧名物理别名，旧导入经 app/runtime/compat/manifest.py SYMBOL_ALIASES 惰性解析
- API 路径与持久化键冻结不变，前端零改动
- 新增兼容守护测试与 docs/rules/07 命名边界规范

app/chain/system.py

@@ -9,7 +9,7 @@ from app.runtime.config import settings
 from app.runtime.extensions.plugin_manager import PluginManager
 from app.runtime.state import SystemHelper
 from app.runtime.log import logger
-from app.schemas import Notification, MessageChannel
+from app.schemas import Message, NotificationChannel
 from app.adapters.network.http import RequestUtils
 from app.adapters.system.host import SystemUtils
 from version import FRONTEND_VERSION, APP_VERSION
@@ -22,24 +22,24 @@ class SystemChain(ChainBase):
 
     _restart_file = "__system_restart__"
 
-    def remote_clear_cache(self, channel: MessageChannel, userid: Union[int, str], source: Optional[str] = None):
+    def remote_clear_cache(self, channel: NotificationChannel, userid: Union[int, str], source: Optional[str] = None):
         """
         清理系统缓存
         """
         self.clear_cache()
-        self.post_message(Notification(
+        self.post_message(Message(
             channel=channel,
             source=source,
             title=f"缓存清理完成！",
             userid=userid,
             save_history=False))
 
-    def restart(self, channel: MessageChannel, userid: Union[int, str], source: Optional[str] = None):
+    def restart(self, channel: NotificationChannel, userid: Union[int, str], source: Optional[str] = None):
         """
         重启系统
         """
         if channel and userid:
-            self.post_message(Notification(
+            self.post_message(Message(
                 channel=channel,
                 source=source,
                 title="系统正在重启，请耐心等候！",
@@ -180,11 +180,11 @@ class SystemChain(ChainBase):
             title += f"当前前端版本：{front_local_version}，远程版本：{front_release_version}"
         return title
 
-    def version(self, channel: MessageChannel, userid: Union[int, str], source: Optional[str] = None):
+    def version(self, channel: NotificationChannel, userid: Union[int, str], source: Optional[str] = None):
         """
         查看当前版本、远程版本
         """
-        self.post_message(Notification(
+        self.post_message(Message(
             channel=channel,
             source=source,
             title=self.__get_version_message(),
@@ -203,13 +203,13 @@ class SystemChain(ChainBase):
             if not isinstance(restart_channel, dict):
                 restart_channel = json.loads(restart_channel)
             channel = next(
-                (channel for channel in MessageChannel.__members__.values() if
+                (channel for channel in NotificationChannel.__members__.values() if
                  channel.value == restart_channel.get('channel')), None)
             userid = restart_channel.get('userid')
 
             # 版本号
             title = self.__get_version_message()
-            self.post_message(Notification(
+            self.post_message(Message(
                 channel=channel,
                 title=f"系统已重启完成！\n{title}",
                 userid=userid,