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

package.json

@@ -77,6 +77,7 @@
     "watch": "tsdown --watch",
     "prepare": "tsdown",
     "test": "vitest run",
+    "test:mount": "bash scripts/e2e-mount.sh",
     "check:consumer-types": "bash scripts/check-consumer-types.sh"
   },
   "license": "MIT",
@@ -137,6 +138,7 @@
     "xterm": "^5.3.0"
   },
   "devDependencies": {
+    "@cordisjs/plugin-loader": "^1.0.0-rc.5",
     "@deepseek-ai/dsh-agent": "^0.1.0-rc.6",
     "@deepseek-ai/dsh-client-locale": "^0.1.0-rc.6",
     "@deepseek-ai/dsh-client-runtime": "^0.1.0-rc.6",
@@ -152,11 +154,11 @@
     "@deepseek-ai/dsh-session": "^0.1.0-rc.6",
     "@deepseek-ai/dsh-settings": "^0.1.0-rc.6",
     "@deepseek-ai/dsh-tools": "^0.1.0-rc.6",
+    "@playwright/test": "^1.62.1",
     "@types/node": "^24.0.0",
     "@types/react": "~18.3.1",
     "@types/react-dom": "~18.3.1",
     "@types/ws": "^8.5.10",
-    "@cordisjs/plugin-loader": "^1.0.0-rc.5",
     "cordis": "^4.0.0-rc.7",
     "jsdom": "^29.1.1",
     "lightningcss": "^1.32.0",