fix: reuse runtime processes across project sessions

Multiple projects could spawn duplicate heavyweight runtimes, while settings
changes and remote reconnection could cancel or strand native conversations.
Share compatible local OpenCode and DeepSeek Harness process owners and
Agent-owned ACP connections, retaining workspace routing, per-session modes,
model attribution, question ownership, targeted cancellation and idle cleanup.

Restore remote pending questions and terminal task projections across reconnect
and desktop restart, and preserve accepted ordinary requests during settings
replacement while cancelling expert-team parents with their replaced scheduler.
Extend regression coverage and Agent type checks. Record measured resource and
real-model validation results, including failures and limitations.

Also include the conversation media-generation design drafts (not an implemented
feature), documentation entry links and dedicated Linux test-directory guidance.
Desktop and Agent changes must be delivered together for shared process results.

Validation: typecheck and lint passed; staged content and documentation links
checked. Prior full regression and live-model evidence are recorded in progress
notes; no new full test suite or model calls were run for this commit.

Release note: 多项目会话现在复用兼容的 OpenCode 和 DeepSeek Harness 进程，减少重复启动并保持工作区、工具和取消隔离。修复远端问答在断线、重启及配置更新后的恢复与状态同步问题，Desktop 与 Agent 需配套更新。

docs/features/assistant-workbar/README.md

@@ -11,7 +11,9 @@
 | [浏览器多实例技术设计](./browser-tabs-technical-design.md) | 浏览器 Tab 身份、Conversation 绑定、IPC、BrowserService 和 MCP 路由 |
 | [实现与验证进度](./progress.md) | 工作区与 Runtime 相关改动的实现事实、验证证据与剩余阻塞 |
 | [执行记录存储与升级回收](./execution-history-storage.md) | 子任务过程差量存储、远程去重、旧库转换、空间回收及升级界面 |
-| [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、托管 Runtime 并行与输出及消息底部请求状态的适配范围 |
+| [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 |
 
-当前尚未拆出独立 User Stories、功能逻辑和 UI 设计文档；相关内容仍保留在两份现有 PRD
-中。浏览器多实例涉及跨进程身份和工具路由，单独使用技术设计文档维护。
+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，
+Runtime 资源状态规则由交互边界文档维护。浏览器多实例和 Runtime 进程复用涉及不同的
+跨进程身份与工具路由，分别使用技术设计文档维护。