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/knowledge-base/external-knowledge-technical-design.md

@@ -33,7 +33,7 @@
 | `src/shared/external-knowledge-contracts.ts` | Provider 配置、实例与绑定输入、目录、测试结果和外部引用定位契约 |
 | `src/shared/knowledge-contracts.ts`、`contracts.ts`、`assistant-contracts.ts` | 现有知识结果、列表和会话引用增加外部字段 |
 | `src/shared/knowledge-reference.ts` | 预检索与 MCP 共用的引用转换和去重键 |
-| `src/main/ipc.ts`、`src/preload/index.ts`、`src/shared/ipc-channels.ts` | 可信发送方检查、Zod 输入解析、类型化跨进程调用 |
+| `src/main/ipc.ts`、`src/main/knowledge/knowledge-ipc.ts`、`src/preload/index.ts`、`src/shared/ipc-channels.ts` | 可信发送方检查、Zod 输入解析、类型化跨进程调用 |
 | `src/renderer/src/ExternalKnowledge.tsx` | 实例 Modal、绑定表单、Provider 配置、外部详情与检索结果 |
 | `KnowledgeWorkspace.tsx`、`App.tsx`、`KnowledgeCitationDialog.tsx` | 统一列表、聊天选择、刷新及历史引用显示 |