feat(v0.2.2): 插件热重载 — watchdog 监听 plugins/ 自动重载

- PluginService.start() 中启动 watchdog Observer
- 监听 plugins/ 下 .py/.yaml/.yml 文件变更
- 1秒防抖，避免重复触发
- 变更后自动卸载→重新加载对应插件
- 插件重载后自动重连网络路由
- PluginService.stop() 清理 observer
- 配置项 hot_reload: true/false 控制

Co-Authored-By: Claude <noreply@anthropic.com>

config/plugins/commands.yaml

@@ -9,10 +9,6 @@ commands:
     permissions:
     - framework.scaffold.plugin
     source: internal
-  echo: &id001
-    description: echo input
-    permissions: []
-    source: plugin.example_plugin
   help:
     description: 显示帮助信息
     permissions:
@@ -33,10 +29,6 @@ commands:
     permissions:
     - framework.permission.read
     source: internal
-  plugin_status: &id002
-    description: show status
-    permissions: []
-    source: plugin.example_plugin
   pm_plugin_status:
     description: '权限管理: 查看插件权限状态'
     permissions:
@@ -92,9 +84,6 @@ commands:
     permissions:
     - framework.command.test
     source: internal
-last_updated: 316707.28385033
-plugin_commands:
-  example_plugin:
-    echo: *id001
-    plugin_status: *id002
-total_commands: 19
+last_updated: 1742.472300949
+plugin_commands: {}
+total_commands: 17