feat: CI 挂载冒烟门禁 — npm 打包 → 真实挂载 DSH → 无头渲染防 crash

新增 plugin-mount job（pnpm test:mount）：
- scripts/e2e-mount.sh：scratch profile 引导（allowBuilds/minimumReleaseAgeExclude 预写）→ 官方
  dsh plugin --profile web add file:<tarball> 挂载（dsh.profile.bundles 协调校验）→ keyless
  dsh web --port 0 → Playwright 无头渲染 → trap 清理
- tests/e2e/mount.e2e.ts：seed 工作区+会话（宿主 RPC）→ 断言 #root 与 [data-dsh-better-sidebar]
  挂载、无崩溃标记（错误条/pageerror/插件 console 错误）→ + 菜单逐个打开内置 tab 深扫
- playwright.config.ts：chromium headless、单 worker、retries 0、失败留 trace/截图/HTML 报告
- vitest exclude 与 *.e2e.ts 命名双保险隔离；exclude 整体替换默认值，须保留默认排除项
- CI 钉住 @deepseek-ai/dsh@0.1.0-rc.6；DSH_TELEMETRY_DISABLED=1；workflow_dispatch + PR 并发取消

已验证：本地端到端全绿；人为注入 tab 组件 crash → 门禁变红（错误条检出），还原后变绿；
typecheck/vitest 全绿；CI 同款 npm 安装 CLI 路径实测通过

vitest.config.ts

@@ -19,5 +19,18 @@ export default defineConfig({
         inline: [/@deepseek-ai\/dsh-client-ui-primitives/],
       },
     },
+    // The Playwright headless-render lane lives in tests/e2e (specs named
+    // *.e2e.ts). Keep vitest from ever collecting it, both by naming (the
+    // default include only matches *.test.* / *.spec.*) and by an explicit
+    // exclude. NOTE: `exclude` REPLACES vitest's defaults, so the standard
+    // node_modules/dist/etc. excludes must be restated here.
+    exclude: [
+      'tests/e2e/**',
+      '**/node_modules/**',
+      '**/dist/**',
+      '**/cypress/**',
+      '**/.{idea,git,cache,output,temp}/**',
+      '**/{karma,rollup,webpack,vite,vitest,jest,ava,babel,nyc,cypress,tsup,build,eslint,prettier}.config.*',
+    ],
   },
 })