feat: 推荐插件目录收录 dsh-sentinel（Tab 注册）

- plugins-tabs.ts 收录 dsh-sentinel（条件驱动的 agent 唤醒系统，注册 dsh-sentinel:watches Tab）
- install 拼接官方一键命令：cd ~/.dsh && dsh plugin --profile web add "github:fuhefei/dsh-sentinel#v0.7.0"
- 新增 pluginSentinelDesc 文案（zh/en）；测试同步（tab 目录不再为空态）

tests/plugin-list.spec.ts

@@ -24,9 +24,10 @@ const catalogs: Array<[string, readonly PluginEntry[]]> = [
 ]
 
 describe('builtin plugin catalogs', () => {
-  it('the viewer catalog has the seeded office plugin, the tab catalog does not', () => {
+  it('the viewer catalog has the office plugin, the tab catalog has the sentinel plugin', () => {
     const ids = (list: readonly PluginEntry[]): string[] => list.map(p => p.id)
     expect(ids(builtinViewerPlugins)).toContain('@huanlin/dsh-plugin-better-sidebar-plugin-office')
+    expect(ids(builtinTabPlugins)).toContain('@dsh-external/dsh-sentinel')
     expect(ids(builtinTabPlugins)).not.toContain('@huanlin/dsh-plugin-better-sidebar-plugin-office')
   })