fix(swarm): WindowsTerminalBackend pidFile health check + 5-state lifecycle

修 wt.exe split-pane fire-and-forget 导致 teammate 假死、TeamDelete 卡死、
kill-while-spawn race 等多个问题。

- 加 waitForPidFile() 在 wt.exe 返回后等 powershell.exe 真启动写 pidFile
  默认 8s timeout，env CLAUDE_WT_PANE_TIMEOUT_MS 覆盖，超时 throw 含完整诊断
- 加 5 态生命周期 (registered/spawning/ready/killing/dead)，sendCommandToPane
  inner Promise 包装 spawnPromise，ready 态重 spawn 直接 throw
- killPane TOCTOU 修正：await spawnPromise 后重读 status；优先用缓存 pane.pid
  避免读盘，Stop-Process 失败也清缓存 + 标 dead 防 PID 复用误杀
- pid 解析严格化：/^\d+$/ + Number.isFinite + >0；移除 dead try/catch
- 构造函数 options 对象注入 pidFileDir（兼容原位置参数）
- 清启动前陈旧 pidFile，killPane fallback 3×500ms retry 兜底

src/utils/swarm/backends/WindowsTerminalBackend.ts

@@ -1,5 +1,5 @@
 import { randomUUID } from 'crypto'
-import { readFile } from 'fs/promises'
+import { readFile, unlink } from 'fs/promises'
 import { join } from 'path'
 import { tmpdir } from 'os'
 import type { AgentColorName } from '@claude-code-best/builtin-tools/tools/AgentTool/agentColorManager.js'
@@ -13,10 +13,15 @@ import type { CreatePaneResult, PaneBackend, PaneId } from './types.js'
 type CommandResult = { stdout: string; stderr: string; code: number }
 type CommandRunner = (command: string, args: string[]) => Promise<CommandResult>
 
+type PaneStatus = 'registered' | 'spawning' | 'ready' | 'killing' | 'dead'
+
 type WindowsTerminalPane = {
   title: string
   mode: 'pane' | 'window'
   pidFile: string
+  status: PaneStatus
+  pid?: number
+  spawnPromise?: Promise<void>
 }
 
 function quotePowerShellString(value: string): string {
@@ -39,8 +44,42 @@ function wrapPowerShellCommand(command: string, pidFile: string): string {
   ].join('; ')
 }
 
-function makePidFile(paneId: string): string {
+const WT_PANE_TIMEOUT_DEFAULT_MS = 8000
-  return join(tmpdir(), `${paneId.replace(/[^a-zA-Z0-9_-]/g, '-')}.pid`)
+const WT_PANE_POLL_INTERVAL_MS = 200
+
+function getWtPaneTimeoutMs(): number {
+  const raw = process.env.CLAUDE_WT_PANE_TIMEOUT_MS
+  if (!raw) return WT_PANE_TIMEOUT_DEFAULT_MS
+  const parsed = Number.parseInt(raw, 10)
+  return Number.isFinite(parsed) && parsed > 0
+    ? parsed
+    : WT_PANE_TIMEOUT_DEFAULT_MS
+}
+
+async function waitForPidFile(
+  pidFile: string,
+  timeoutMs: number,
+): Promise<number> {
+  const deadline = Date.now() + timeoutMs
+  let lastErr: unknown
+  while (Date.now() < deadline) {
+    try {
+      const content = (await readFile(pidFile, 'utf-8')).trim()
+      if (!/^\d+$/.test(content)) {
+        lastErr = new Error(
+          `pidFile content not a valid pid: ${JSON.stringify(content)}`,
+        )
+      } else {
+        const pid = Number.parseInt(content, 10)
+        if (Number.isFinite(pid) && pid > 0) return pid
+        lastErr = new Error(`pidFile content parsed to invalid pid: ${pid}`)
+      }
+    } catch (err) {
+      lastErr = err
+    }
+    await new Promise(r => setTimeout(r, WT_PANE_POLL_INTERVAL_MS))
+  }
+  throw lastErr ?? new Error('pidFile never appeared')
 }
 
 /**
@@ -58,10 +97,40 @@ export class WindowsTerminalBackend implements PaneBackend {
 
   private panes = new Map<PaneId, WindowsTerminalPane>()
 
+  private readonly runCommand: CommandRunner
+  private readonly getPlatformValue: () => Platform
+  private readonly pidFileDir: string
+
   constructor(
-    private readonly runCommand: CommandRunner = execFileNoThrow,
+    runCommandOrOptions?:
-    private readonly getPlatformValue: () => Platform = getPlatform,
+      | CommandRunner
-  ) {}
+      | {
+          runCommand?: CommandRunner
+          getPlatform?: () => Platform
+          pidFileDir?: string
+        },
+    getPlatformValue?: () => Platform,
+  ) {
+    if (
+      typeof runCommandOrOptions === 'function' ||
+      runCommandOrOptions === undefined
+    ) {
+      this.runCommand = runCommandOrOptions ?? execFileNoThrow
+      this.getPlatformValue = getPlatformValue ?? getPlatform
+      this.pidFileDir = tmpdir()
+    } else {
+      this.runCommand = runCommandOrOptions.runCommand ?? execFileNoThrow
+      this.getPlatformValue = runCommandOrOptions.getPlatform ?? getPlatform
+      this.pidFileDir = runCommandOrOptions.pidFileDir ?? tmpdir()
+    }
+  }
+
+  private makePidFile(paneId: string): string {
+    return join(
+      this.pidFileDir,
+      `${paneId.replace(/[^a-zA-Z0-9_-]/g, '-')}.pid`,
+    )
+  }
 
   async isAvailable(): Promise<boolean> {
     if (this.getPlatformValue() !== 'windows') {
@@ -92,7 +161,8 @@ export class WindowsTerminalBackend implements PaneBackend {
     this.panes.set(paneId, {
       title: name,
       mode: 'pane',
-      pidFile: makePidFile(paneId),
+      pidFile: this.makePidFile(paneId),
+      status: 'registered',
     })
     return { paneId, isFirstTeammate }
   }
@@ -106,7 +176,8 @@ export class WindowsTerminalBackend implements PaneBackend {
     this.panes.set(paneId, {
       title: name,
       mode: 'window',
-      pidFile: makePidFile(paneId),
+      pidFile: this.makePidFile(paneId),
+      status: 'registered',
     })
     return { paneId, isFirstTeammate: false, windowName }
   }
@@ -121,32 +192,95 @@ export class WindowsTerminalBackend implements PaneBackend {
       throw new Error(`Unknown Windows Terminal pane id: ${paneId}`)
     }
 
-    const launcher = wrapPowerShellCommand(command, pane.pidFile)
+    // 拒绝 ready 态重 spawn（避免同 pidFile 双进程竞争）
-    // wt.exe treats ';' as its own command separator, which breaks
+    if (pane.status === 'ready' || pane.status === 'killing') {
-    // multi-statement PowerShell commands passed via -Command. Encode the
-    // entire script as Base64 UTF-16LE and use -EncodedCommand instead.
-    const encoded = Buffer.from(launcher, 'utf16le').toString('base64')
-    const args =
-      pane.mode === 'window'
-        ? ['-w', '-1', 'new-tab', '--title', pane.title]
-        : ['-w', '0', 'split-pane', '--vertical', '--title', pane.title]
-
-    const result = await this.runCommand('wt.exe', [
-      ...args,
-      'powershell.exe',
-      '-NoLogo',
-      '-NoProfile',
-      '-ExecutionPolicy',
-      'Bypass',
-      '-EncodedCommand',
-      encoded,
-    ])
-
-    if (result.code !== 0) {
       throw new Error(
-        `Failed to launch Windows Terminal teammate ${paneId}: ${result.stderr}`,
+        `Pane ${paneId} already spawned (status=${pane.status}); create a new pane to re-launch`,
       )
     }
+    if (pane.status === 'spawning') {
+      throw new Error(
+        `Pane ${paneId} is currently spawning; wait for the in-flight launch to complete`,
+      )
+    }
+    if (pane.status === 'dead') {
+      throw new Error(`Pane ${paneId} is dead; create a new pane`)
+    }
+    // pane.status === 'registered' → 继续
+
+    // 提前赋值 spawnPromise 在任何 await 前（inner Promise 包装）
+    // Attach a no-op .catch() immediately to prevent unhandled rejection warnings
+    // in case killPane never awaits spawnPromise (e.g. sendCommandToPane fails
+    // before killPane is called).
+    let resolveSpawn!: () => void
+    let rejectSpawn!: (err: unknown) => void
+    const spawnPromise = new Promise<void>((res, rej) => {
+      resolveSpawn = res
+      rejectSpawn = rej
+    })
+    // Silence unhandled-rejection: killPane may .catch() this later, but if
+    // the pane dies before any kill is attempted, the rejection must not leak.
+    spawnPromise.catch(() => {})
+    pane.status = 'spawning'
+    pane.spawnPromise = spawnPromise
+
+    try {
+      const launcher = wrapPowerShellCommand(command, pane.pidFile)
+      // wt.exe treats ';' as its own command separator, which breaks
+      // multi-statement PowerShell commands passed via -Command. Encode the
+      // entire script as Base64 UTF-16LE and use -EncodedCommand instead.
+      const encoded = Buffer.from(launcher, 'utf16le').toString('base64')
+      const args =
+        pane.mode === 'window'
+          ? ['-w', '-1', 'new-tab', '--title', pane.title]
+          : ['-w', '0', 'split-pane', '--vertical', '--title', pane.title]
+
+      await unlink(pane.pidFile).catch(() => {})
+
+      const result = await this.runCommand('wt.exe', [
+        ...args,
+        'powershell.exe',
+        '-NoLogo',
+        '-NoProfile',
+        '-ExecutionPolicy',
+        'Bypass',
+        '-EncodedCommand',
+        encoded,
+      ])
+
+      if (result.code !== 0) {
+        throw new Error(
+          `Failed to launch Windows Terminal teammate ${paneId}: ${result.stderr}`,
+        )
+      }
+
+      const timeoutMs = getWtPaneTimeoutMs()
+      let pid: number
+      try {
+        pid = await waitForPidFile(pane.pidFile, timeoutMs)
+      } catch (err) {
+        throw new Error(
+          `Windows Terminal pane failed to launch within ${timeoutMs}ms\n` +
+            `  paneId: ${paneId}\n` +
+            `  pidFile: ${pane.pidFile}\n` +
+            `  wt.exe stdout: ${result.stdout || '(empty)'}\n` +
+            `  wt.exe stderr: ${result.stderr || '(empty)'}\n` +
+            `  underlying: ${err instanceof Error ? err.message : String(err)}\n` +
+            `  override timeout via env CLAUDE_WT_PANE_TIMEOUT_MS`,
+        )
+      }
+
+      pane.pid = pid
+      pane.status = 'ready'
+      resolveSpawn()
+    } catch (err) {
+      pane.status = 'dead'
+      pane.pid = undefined
+      rejectSpawn(err)
+      throw err
+    } finally {
+      pane.spawnPromise = undefined
+    }
   }
 
   async setPaneBorderColor(
@@ -189,26 +323,69 @@ export class WindowsTerminalBackend implements PaneBackend {
       return false
     }
 
-    let pid: number
+    // 1. 解 kill-while-spawn race：await spawn 完成（不论成功失败）
-    try {
+    if (pane.status === 'spawning' && pane.spawnPromise) {
-      pid = Number.parseInt((await readFile(pane.pidFile, 'utf-8')).trim(), 10)
+      await pane.spawnPromise.catch(() => {})
-    } catch {
+    }
+
+    // 2. TOCTOU 修正：重读 status/pid
+    if (pane.status === 'dead') {
       this.panes.delete(paneId)
       return false
     }
-
+    if (pane.status !== 'ready') {
-    if (!Number.isFinite(pid)) {
+      // 还在其它非终态（理论不可达，保险）
-      this.panes.delete(paneId)
       return false
     }
 
+    pane.status = 'killing'
+
+    // 3. 优先用缓存 pid
+    let pid: number | undefined = pane.pid
+
+    // 4. fallback：缓存没有则读盘（保留 retry 3×500ms）
+    if (pid === undefined) {
+      let pidContent: string | null = null
+      for (let attempt = 0; attempt < 3; attempt++) {
+        try {
+          pidContent = (await readFile(pane.pidFile, 'utf-8')).trim()
+          break
+        } catch {
+          if (attempt === 2) {
+            pane.status = 'dead'
+            this.panes.delete(paneId)
+            return false
+          }
+          await new Promise(r => setTimeout(r, 500))
+        }
+      }
+      if (!pidContent || !/^\d+$/.test(pidContent)) {
+        pane.status = 'dead'
+        this.panes.delete(paneId)
+        return false
+      }
+      const parsed = Number.parseInt(pidContent, 10)
+      if (!Number.isFinite(parsed) || parsed <= 0) {
+        pane.status = 'dead'
+        this.panes.delete(paneId)
+        return false
+      }
+      pid = parsed
+    }
+
+    // 5. 执行 Stop-Process
     const result = await this.runCommand('powershell.exe', [
       '-NoLogo',
       '-NoProfile',
       '-Command',
       `Stop-Process -Id ${pid} -Force -ErrorAction Stop`,
     ])
+
+    // 6. 不管成功失败都清缓存 + 标 dead + 从 map 删（防 PID 复用误杀）
+    pane.pid = undefined
+    pane.status = 'dead'
     this.panes.delete(paneId)
+
     logForDebugging(
       `[WindowsTerminalBackend] killPane ${paneId} pid=${pid} code=${result.code}`,
     )