feat: open local runtime clients from the composer

Add composer shortcuts for local Continue and OpenCode terminals and the official DeepSeek Harness Web client, using the current project and model bridge. Manage browser service reuse, stop actions and terminal cleanup. Upgrade DeepSeek Harness to 0.1.7-rc.2 and Cordis to 4.0.4.

Include the coordinated IPC handler extraction and related tests and documentation. Remote native-client coordinator wiring, managed Node consolidation, Ask MCP mappings and full desktop/package acceptance remain unfinished; this commit records the implemented local workflow and supporting SSH groundwork.

Validation: typecheck and lint passed; 267 focused tests passed and 5 skipped. No new real-provider calls were made for this commit. Prior real-model evidence and remaining acceptance work are documented in the feature progress files.

Release note: 本地项目选择 Continue 或 OpenCode 后，可从输入框下方打开原生终端；选择 DS 后，可打开使用当前项目和模型的官方 Web 客户端。客户端使用独立会话，DS 网页关闭后服务继续运行，可在 GoodBuddy 中停止；远程入口尚未完成。

docs/features/assistant-workbar/README.md

@@ -18,6 +18,7 @@
 | [执行记录存储与升级回收](./execution-history-storage.md) | 子任务差量存储、远程去重、旧库转换、会话置顶、摘要与完整历史按需读取、内存引用释放 |
 | [Runtime 交互边界](./runtime-interactions.md) | 原生权限、结构化问答、后台拒绝、终端交互、并行与输出、消息请求状态及资源生命周期规则 |
 | [Runtime 进程复用技术设计](./runtime-process-reuse-technical-design.md) | 跨 Runtime 资源调研、锁定协议证据、进程与会话拆分、远端模型桥、实施顺序和性能验收 |
+| [Runtime 原生客户端启动方案](./runtime-native-client-proposal.md) | Local terminal/DS Web shortcut requirements, startup rules, current integration, validation boundaries and remaining remote/resource work |
 | [Runtime 执行清单技术设计](./runtime-checklist-technical-design.md) | OC/CN 原生清单提取、远程 Agent 传递复用、消息恢复与真实部署验收；尚未实现 |
 
 当前尚未拆出独立 User Stories、功能逻辑和 UI 设计文档；产品场景与验收保留在现有 PRD，