fix(market): 移除公开版 cordis peer 并迁移类型基底到 @deepseek-ai/cordis

DSH 市场（dsh-community-market）预览硬拒依赖字段出现 'cordis'
（dependencies/peerDependencies/optionalDependencies 任一字段、
optional 均无效），导致 dshfind/1024Store 目录拿不到
repository_backlink 验证目标，点击安装报
"This catalog item has no verified install target"。

- package.json: 删除 cordis peer + peerDependenciesMeta；版本 0.15.2
- context-types.ts: Context 基底改 @deepseek-ai/cordis，结构服务面改
  交集（避免 DS host/client 对同一成员类型不同导致的 TS2717 merge
  冲突），仅保留 betterSidebar 的 module augmentation；删除
  declare module 'cordis'
- client/index.tsx: 4 处 effect 体失败分支改返回 no-op disposer
  （vendored cordis effect 契约拒绝 undefined 形状）
- 新增 tests/market-manifest.spec.ts：无 cordis 依赖字段、打包产物
  无生命周期脚本、bundle patch 安全路径、仓库身份、精确稳定版本
- 消费者检查扩展：@deepseek-ai/cordis 路径的 Context augmentation
  断言；文档示例同步迁移

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dsh-better-sidebar",
-  "version": "0.15.1",
+  "version": "0.15.2",
   "description": "DSH web plugin: a VSCode-like right sidebar (explorer / editor / terminal / git / browser), isolated per conversation session. Exposes a service for other plugins to register sidebar tabs and file viewers.",
   "type": "module",
   "repository": {
@@ -99,15 +99,9 @@
     "@deepseek-ai/dsh-settings": "^0.1.0-rc.8",
     "@deepseek-ai/dsh-subagent": "^0.1.0-rc.8",
     "@deepseek-ai/dsh-tools": "^0.1.0-rc.8",
-    "cordis": "^4.0.0-rc.8",
     "react": "^18.2.0",
     "react-dom": "^18.2.0"
   },
-  "peerDependenciesMeta": {
-    "cordis": {
-      "optional": true
-    }
-  },
   "dependencies": {
     "@codemirror/commands": "^6.10.4",
     "@codemirror/lang-cpp": "^6.0.3",