feat: integrate 5 feature branches + daemon/job 命令层级化 + 跨平台后台引擎 + TypeScript 错误修复

Squashed merge of:
1. fix/mcp-tsc-errors — 修复上游 MCP 重构后的 tsc 错误和测试失败
2. feat/pipe-mute-disconnect — Pipe IPC 逻辑断开、/lang 命令、mute 状态机
3. feat/stub-recovery-all — 实现全部 stub 恢复 (task 001-012)
4. feat/kairos-activation — KAIROS 激活解除阻塞 + 工具实现
5. codex/openclaw-autonomy-pr — 自治权限系统、运行记录、managed flows

Additional:
6. daemon/job 命令层级化重构 (subcommand 架构)
7. 跨平台后台引擎抽象 (detached/tmux engines)
8. 修复 src/ 中 43 个预存在的 TypeScript 类型错误
9. 修复 langfuse isolated test mock 完整性
10. 修复 CodeRabbit 审查的 Critical/Major/Minor 问题
11. remote-control-server logger 抽象 (测试 stderr 静默化)
12. /simplify 审查修复 (代码复用、质量、效率)

src/cli/bg/engines/detached.ts

@@ -0,0 +1,51 @@
+import { spawn } from 'child_process'
+import { openSync, closeSync, mkdirSync } from 'fs'
+import { dirname } from 'path'
+import type { BgEngine, BgStartOptions, BgStartResult, SessionEntry } from '../engine.js'
+import { tailLog } from '../tail.js'
+
+export class DetachedEngine implements BgEngine {
+  readonly name = 'detached' as const
+
+  async available(): Promise<boolean> {
+    return true
+  }
+
+  async start(opts: BgStartOptions): Promise<BgStartResult> {
+    mkdirSync(dirname(opts.logPath), { recursive: true })
+
+    const logFd = openSync(opts.logPath, 'a')
+    const entrypoint = process.argv[1]!
+
+    const child = spawn(process.execPath, [entrypoint, ...opts.args], {
+      detached: true,
+      stdio: ['ignore', logFd, logFd],
+      env: {
+        ...opts.env,
+        CLAUDE_CODE_SESSION_KIND: 'bg',
+        CLAUDE_CODE_SESSION_NAME: opts.sessionName,
+        CLAUDE_CODE_SESSION_LOG: opts.logPath,
+      } as Record<string, string>,
+      cwd: opts.cwd,
+    })
+
+    child.unref()
+    closeSync(logFd)
+
+    const pid = child.pid ?? 0
+
+    return {
+      pid,
+      sessionName: opts.sessionName,
+      logPath: opts.logPath,
+      engineUsed: 'detached',
+    }
+  }
+
+  async attach(session: SessionEntry): Promise<void> {
+    if (!session.logPath) {
+      throw new Error(`Session ${session.sessionId} has no log path.`)
+    }
+    await tailLog(session.logPath)
+  }
+}