fix: prevent runtime permission stalls and Agent reconnect failures

Execute could stall on workspace-external access or native child-session
permissions, while structured questions could be lost or answered incorrectly.
Route owned OpenCode descendant interactions, correct Continue question and
custom-answer handling, and resolve DSH Execute ACP permissions without a
second approval. Ask remains read-only and unrelated sessions stay isolated.

Restore the required DSH session projection service. Reuse offline OpenCode
configuration by plugin version, remove unused npm shims from remote payloads,
normalize dependency modes, and accept real compound descriptors up to 4 MiB.
Fix intermittent Agent attach rejection and closed-handshake waits.

Add focused and real-Runtime regressions, document interaction boundaries and
validation evidence, and include the existing application/tool navigation
design drafts. Those navigation changes are design-only, not implemented UI.

Validation: full suite 3597 passed, 0 failed, 61 skipped across 338 files;
typecheck, lint, release-note verification, whitespace and relative-link checks
passed. Current-source Linux x64 installation, Ask/Execute, native subagent
external writes, reconnect and stop/bootstrap passed with 10 completed real
model calls, 13 native endpoint tests and 20 consecutive handshakes.
System sleep/wake and release CI packaging remain unverified.

Release note: 修复 Execute 访问工作区外目录或运行原生子代理时卡在权限等待的问题，并恢复 OpenCode 与 Continue 结构化问答的正确转交。修复远程 Agent 安装与重连失败；Ask 仍保持只读，任意终端密码或业务确认不会自动代答。

UI-DESIGN.md

@@ -323,8 +323,9 @@
   能力自动增删稳定应用目录入口。
 - Tab 行只显示已打开实例，行末始终提供“+”普通按钮；点击后在内容区打开应用选择页。
   “+”不使用 `tab` 语义，也不能因为终端或其他应用已经打开而消失。
-- 应用注册表声明单实例或多实例。单实例重复选择时聚焦已有 Tab；终端从首期开始支持
-  多实例，每次选择创建独立 Tab 和 Shell Session。
+- 应用注册表声明单实例或多实例。在工作栏“+”目录中，单实例重复选择时聚焦已有 Tab；终端
+  从首期开始支持多实例，每次选择创建独立 Tab 和 Shell Session。主侧栏系统工具快捷入口
+  可以聚焦当前执行空间中最近使用的终端，额外终端仍从“+”目录创建。
 - Task Center 是 Task 的单例应用级索引，不使用“跟随 / 固定目标”多实例模式。每个 Task
   只关联一条 Conversation，一条 Conversation 可以关联多个 Task；列表不得复制会话内容，
   也不得把 Job/Run 提升为可导航 UI 对象。