fix(rebase): migrate the replayed stack onto current master APIs

The linear replay carried each commit's own lineage, so this checkpoint
restores the master-owned surfaces the conflicted regions clobbered and
migrates branch-owned code to master's post-rebase APIs:

- rebuild subprocess-local spawn.ts on master's tree-exit-observer
  machinery, keeping the branch's win32 childEnv key semantics and the
  Linux zombie-quiescence probe; the zombie test reaps its survivor
  directly since a confirmed-absent verdict is a permanent
  no-more-signals boundary
- migrate pty-local test stubs to the Inbox-model Agent interface,
  Session.create, runnerFailureRules, and the new turn/start payload
- implement the seam's resolveExecutable/spawnTerminal abstracts in the
  new pwsh-local and tool-fs-search test fakes
- restore code-runtime, atomic-write, pwsh-local, and app-boot to
  master's exact content (the net-zero code-runtime churn is pruned
  from this history) and drop rename-detection graft debris
- re-apply the PR's architecture rows and execution-world paragraph,
  re-record bilingual pairings, regenerate catalogs, and reconcile the
  lockfile

packages/subprocess/subprocess-local/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/subprocess/subprocess-local/README.md
-README.md: b901a69d6cfd45a084711ba0d32e555c481fd626
-README.zh.md: 5723dc99ff955c5f4b07ea96e7d2134100d9fd6a
+README.md: 087ca24a3207cb8cb1568769a462fbbb010aaa35
+README.zh.md: 4d400906f71b653ce2be95a22751fd9893f447bd

packages/subprocess/subprocess-local/README.md

@@ -6,9 +6,9 @@ Local implementation of the [`@deepseek-ai/dsh-subprocess`](../subprocess/README
 
 ## Behavior (and where it came from)
 
-- **Detached process trees with platform-correct signalling** — POSIX children are spawned `detached` (own process group) and signalled by negative pgid with a direct-child fallback; Windows terminates the tree via `taskkill /PID <pid> /T /F` (injectable for tests). `terminate()` — the handle's only termination verb — sends SIGTERM then SIGKILL after the spec's grace (OpenCode's escalation; pipelines and subshells die with the parent) and is a no-op once the tree is gone; `waitForExit()` polls whole-tree liveness so consumer teardown confirms real quiescence. After the leader exits, still-open pipes receive the same bounded drain grace so a surviving descendant cannot hold the outcome open indefinitely. ESRCH is tolerated; daemons that re-parent away from the group can still survive — the same caveat as the surveyed tools.
+- **Detached process trees with platform-correct signalling** — POSIX children are spawned `detached` (own process group) and signalled by negative pgid with a direct-child fallback; Windows terminates the tree via `taskkill /PID <pid> /T /F`. `terminate()` — the handle's only termination verb — sends SIGTERM then SIGKILL after the spec's grace (OpenCode's escalation; pipelines and subshells die with the parent) and is a no-op once the tree is gone; `waitForExit()` polls whole-tree liveness so consumer teardown confirms real quiescence. After the leader exits, still-open pipes receive the same bounded drain grace so a surviving descendant cannot hold the outcome open indefinitely. ESRCH is tolerated; daemons that re-parent away from the group can still survive — the same caveat as the surveyed tools.
 - **Per-stream dispositions** — `'pipe'` hands the raw stream to the caller untouched (protocol framing stays consumer-owned); `'inherit'` passes the parent descriptor through; collect mode keeps the in-memory TAIL beyond its cap (errors and results cluster at the end — pi/OpenCode rationale) while the FULL stream is appended to a private temp file when a spill cap is configured — omitting `spill` keeps only the tail, the diagnostic shape. A stream larger than the spill cap discards its now-incomplete spill and returns only the marked truncated tail; spill fds are sealed at settlement, and a failed final close withholds the path rather than advertising an incomplete file. Spill files are `0600` with random names under a lazily-created `0700` per-process directory.
-- **Credential scrub + explicit merge** — `process.env` minus credential-shaped vars (`*KEY*`/`*SECRET*`/`*TOKEN*`) and all ambient `DSH_*` names; the spec's explicit `env` merges after that scrub with no namespace validation, so a deliberately supplied credential or current `DSH_*` fact wins while stale nested-harness identity cannot leak in ambiently. Supplied stdin is written and closed; otherwise fd 0 is `/dev/null`. See the [stdin/env Agent Note](../../../.agents/notes/implemented/architecture/2026-06-30-bash-stdin-env-trusted-plugin-surface.md) and [managed environment Agent Note](../../../.agents/notes/implemented/feature/2026-07-10-agent-session-identity-and-log-location.md).
+- **Credential scrub + explicit merge** — `process.env` minus credential-shaped vars (`*KEY*`/`*PASSWORD*`/`*SECRET*`/`*TOKEN*`) and all ambient `DSH_*` names; the spec's explicit `env` merges after that scrub with no namespace validation, so a deliberately supplied credential or current `DSH_*` fact wins while stale nested-harness identity cannot leak in ambiently. Supplied stdin is written and closed; otherwise fd 0 is `/dev/null`. See the [stdin/env Agent Note](../../../.agents/notes/implemented/architecture/2026-06-30-bash-stdin-env-trusted-plugin-surface.md) and [managed environment Agent Note](../../../.agents/notes/implemented/feature/2026-07-10-agent-session-identity-and-log-location.md).
 - **Offset-based reads** — collect-mode readers return deltas in whole-stream byte coordinates; the service never holds a cursor, so consumer-owned cursors (the bash background read path) and full-stream re-reads coexist, before and after settlement.
 - **Executable lookup** — `resolveExecutable` checks absolute files or searches the scrubbed effective PATH with platform-aware executable extensions; relative paths containing separators are rejected at the seam, and relative PATH entries resolve from the host process cwd.
 - **Terminal-process ownership** — `spawnTerminal` allocates `node-pty`, bridges UTF-8 terminal text, inspects and signals the current foreground process group, and exposes one awaited termination operation that sweeps descendants before and after terminating the top-level shell. Each foreground inspection retains exact identities from the rooted tree; Linux also enumerates the POSIX session after its leader exits. A previously observed macOS descendant and any same-session Linux member therefore remain fenced after reparenting, while pid/start identity prevents cleanup from following PID reuse. The higher PTY backend owns prompt readiness, buffers, and model-facing operations.
@@ -24,10 +24,10 @@ No direct invalidation; the named consumers own any request-prefix changes.
 
 ## Known Limitations and Deferred Work
 
-- **Windows tree support is best-effort and untested in CI** — termination routes through `taskkill /PID <pid> /T /F` with all outcomes contained (absent tree, races, missing binary), and liveness falls back to the direct-child boundary; the suites cover the routing through an injected runner only, and `packages/subprocess/*` is excluded from the Windows test matrix.
+- **Windows tree support is best-effort** — termination routes through `taskkill /PID <pid> /T /F` with all outcomes contained (absent tree, races, missing binary), and liveness falls back to the direct-child boundary.
 - **Terminal process inspection is Linux/macOS only** — the terminal primitive fails when its inspector has no supported platform implementation; Linux exact probes cover x64 and arm64, while macOS uses `ps` snapshots.
 - **A daemonized terminal descendant can still escape the observable boundary** — on macOS, a child that reparents before any foreground-inspection snapshot is no longer discoverable from the `node-pty` root; on Linux, a child that calls `setsid` leaves both the tree and owned terminal session. The local provider does not add a continuous process-table monitor.
-- **The credential scrub is a name heuristic** — `*KEY*`/`*SECRET*`/`*TOKEN*` only; differently-named secrets (e.g. `*PASSWORD*`) pass through, and a whitelist for over-scrubbed vars is noted future work.
+- **The credential scrub is a name heuristic** — `*KEY*`/`*PASSWORD*`/`*SECRET*`/`*TOKEN*` only; differently-named secrets (e.g. `*PASSPHRASE*`) pass through, and a whitelist for over-scrubbed vars is noted future work.
 - **Completed spill files are not deleted** — bounded full-output recovery files (and the private per-process spill dir) accumulate under the OS tmpdir until something external cleans them; oversize incomplete spills are discarded and deletion is attempted immediately, but a cleanup failure can leave a bounded file behind.
 
 The raw process handling lives in `src/spawn.ts`; `src/index.ts` is the service wiring.

packages/subprocess/subprocess-local/README.zh.md

@@ -6,9 +6,9 @@
 
 ## 行为（以及设计来源）
 
-- **以适合平台的方式发送信号的 detached 进程树**：POSIX 子进程使用 `detached` spawn（拥有独立进程组），信号以负 pgid 发送并以直接子进程作为回退；Windows 通过 `taskkill /PID <pid> /T /F` 终止进程树（可为测试注入）。`terminate()`（句柄唯一的终止操作）先发送 SIGTERM，经过 spec 的宽限期后再发送 SIGKILL（沿用 OpenCode 的升级策略；流水线与子 shell 会随父进程一起结束），进程树消亡后为空操作；`waitForExit()` 轮询整棵进程树的存活状态，使消费方的拆卸能确认真正的完全停稳。组长进程退出后，仍然打开的管道也只获得同样有界的排空宽限期，因此存活的后代进程无法无限期地拖住结果不结算。系统会容忍 ESRCH；重新指定父进程并脱离该组的 daemon 仍可能存活，这与所调研工具的局限相同。
+- **以适合平台的方式发送信号的 detached 进程树**：POSIX 子进程使用 `detached` spawn（拥有独立进程组），信号以负 pgid 发送并以直接子进程作为回退；Windows 通过 `taskkill /PID <pid> /T /F` 终止进程树。`terminate()`（句柄唯一的终止操作）先发送 SIGTERM，经过 spec 的宽限期后再发送 SIGKILL（沿用 OpenCode 的升级策略；流水线与子 shell 会随父进程一起结束），进程树消亡后为空操作；`waitForExit()` 轮询整棵进程树的存活状态，使消费方的拆卸能确认真正的完全停稳。组长进程退出后，仍然打开的管道也只获得同样有界的排空宽限期，因此存活的后代进程无法无限期地拖住结果不结算。系统会容忍 ESRCH；重新指定父进程并脱离该组的 daemon 仍可能存活，这与所调研工具的局限相同。
 - **按流划分的处置方式**：`'pipe'` 把原始流原样交给调用方（协议分帧仍归消费方所有）；`'inherit'` 直通父进程的描述符；收集模式（collect）在输出超过上限后于内存中保留尾部（错误与结果通常聚集在末尾，沿用 pi/OpenCode 的理由），并在配置了 spill 上限时把完整流追加到一个私有临时文件；省略 `spill` 则只保留用于诊断的尾部。某条流大于 spill 上限时，会丢弃已不完整的 spill，仅返回带截断标记的尾部；spill 文件描述符在结算时封存，最终关闭失败时则不公布路径，以免声称存在不完整的文件。spill 文件权限为 `0600`、名称随机，位于按需创建、权限为 `0700` 的每进程目录之下。
-- **凭据清除 + 显式合并**：以 `process.env` 为基础，移除形似凭据的变量（`*KEY*`／`*PASSWORD*`／`*SECRET*`／`*TOKEN*`）和所有环境中已有的 `DSH_*` 名称；spec 的显式 `env` 在该清除之后合并且不做命名空间校验，因此有意提供的凭据或当前 `DSH_*` 事实会胜出，而陈旧的嵌套 harness 身份无法从环境中隐式漏入。提供的 stdin 会被写入后关闭；否则 fd 0 指向 `/dev/null`。参见 [stdin/env Agent Note（agent 决策记录）](../../../.agents/notes/implemented/architecture/2026-06-30-bash-stdin-env-trusted-plugin-surface.md)与[受管环境 Agent Note](../../../.agents/notes/implemented/feature/2026-07-10-agent-session-identity-and-log-location.md)。
+- **凭据清除 + 显式合并**：以 `process.env` 为基础，移除形似凭据的变量（`*KEY*`／`*PASSWORD*`／`*SECRET*`／`*TOKEN*`）和所有环境中已有的 `DSH_*` 名称；spec 的显式 `env` 在该清除之后合并且不做命名空间校验，因此有意提供的凭据或当前 `DSH_*` 事实会胜出，而陈旧的嵌套 harness 身份无法从环境中隐式漏入。提供的 stdin 会被写入后关闭；否则 fd 0 指向 `/dev/null`。参见 [stdin/env Agent Note](../../../.agents/notes/implemented/architecture/2026-06-30-bash-stdin-env-trusted-plugin-surface.md)与[受管环境 Agent Note](../../../.agents/notes/implemented/feature/2026-07-10-agent-session-identity-and-log-location.md)。
 - **基于偏移量的读取**：收集模式的读取器按完整流的字节坐标返回增量；服务自身从不持有游标，因此消费方自有的游标（bash 的后台读取路径）与完整流重读可以共存，结算前后皆然。
 - **可执行文件查找**：`resolveExecutable` 检查绝对文件，或根据平台可执行文件扩展名在清理后的有效 PATH 中搜索；含分隔符的相对路径在接缝处被拒绝，相对 PATH 条目从宿主进程 cwd 解析。
 - **终端进程所有权**：`spawnTerminal` 分配 `node-pty`，桥接 UTF-8 终端文本，检查当前前台进程组并向其发送信号，还会公开一项须等待的终止操作，在终止顶层 shell 前后清理后代进程。每次前台检查都会保留根进程树中的精确身份；Linux 还会在 POSIX 会话 leader 退出后枚举该会话。因此，之前观察到的 macOS 后代以及同会话 Linux 成员在重新设定父进程后仍受围栏保护，pid/start 身份则防止清理跟随 PID 复用。上层 PTY 后端负责提示符就绪、缓冲区与面向模型的操作。
@@ -24,7 +24,7 @@
 
 ## 已知限制与暂缓事项
 
-- **Windows 进程树支持仅为尽力而为，且未经 CI 测试**：终止经由 `taskkill /PID <pid> /T /F` 完成，所有结果都被就地吸收，不向外抛出（进程树已不存在、竞态、二进制缺失），存活探测则回退到直接子进程边界；测试套件只通过注入的运行器覆盖这条路由，且 `packages/subprocess/*` 被排除在 Windows 测试矩阵之外。
+- **Windows 进程树支持仅为尽力而为**：终止经由 `taskkill /PID <pid> /T /F` 完成，所有结果都被就地吸收，不向外抛出（进程树已不存在、竞态、二进制缺失），存活探测则回退到直接子进程边界。
 - **终端进程检查仅支持 Linux／macOS**：检查器没有受支持的平台实现时，终端原语会失败；Linux 精确探针覆盖 x64 与 arm64，macOS 则使用 `ps` 快照。
 - **守护化的终端后代仍可能逃出可观察边界**：在 macOS 上，子进程如果在任何前台检查快照之前重新设定父进程，将无法再从 `node-pty` 根进程发现；在 Linux 上，调用 `setsid` 的子进程会同时离开进程树与自有终端会话。本地提供方不会新增持续进程表监视器。
 - **凭据清除依赖名称启发式规则**：只匹配 `*KEY*`／`*PASSWORD*`／`*SECRET*`／`*TOKEN*`；名称不同的 secret（例如 `*PASSPHRASE*`）会继续传递，对误删变量引入白名单属于已记录的后续工作。

packages/subprocess/subprocess-local/src/spawn.ts

@@ -15,6 +15,7 @@ import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { setTimeout as sleepMs } from 'node:timers/promises'
 import { scrubbedParentEnv } from '@deepseek-ai/dsh-subprocess'
+import { MAX_TIMER_DELAY_MS } from '@deepseek-ai/dsh-timeout'
 import type {
   CollectedOutput,
   SubprocessCollect,
@@ -27,16 +28,16 @@ import { linuxProcessGroupHasLiveMembers } from './process-inspector.ts'
 
 /**
  * Build a child environment: explicit caller entries override the scrubbed
- * parent base using the target platform's environment-key semantics, so a
- * deliberately supplied credential or current `DSH_*` fact wins over the
- * scrub that dropped its ambient namesake.
- * @param extra - explicit caller entries merged after the scrubbed parent.
+ * parent base using the target platform's environment-key semantics. A string
+ * deliberately restores or overrides an entry; an explicit `undefined`
+ * tombstone removes an ordinary ambient entry.
+ * @param extra - explicit caller entries and tombstones, merged after the scrub.
  * @returns the environment to hand to `spawn` for the child process.
  */
-export function childEnv(extra?: Readonly<Record<string, string>>): NodeJS.ProcessEnv {
+export function childEnv(extra?: Readonly<NodeJS.ProcessEnv>): NodeJS.ProcessEnv {
   const env = scrubbedParentEnv()
   if (process.platform !== 'win32') return { ...env, ...extra }
-  let entries = Object.entries(env)
+  let entries: [string, string | undefined][] = Object.entries(env)
   for (const [key, value] of Object.entries(extra ?? {})) {
     const normalized = key.toUpperCase()
     entries = entries.filter(([inherited]) => inherited.toUpperCase() !== normalized)
@@ -310,8 +311,12 @@ function signalTree(
  * @param spec - fully resolved argv, cwd, stdio, grace, cancellation, environment.
  * @param internals - test-only spill-directory, platform, and taskkill overrides.
  * @returns live subprocess handle.
+ * @throws when `graceMs` cannot be represented by one Node timer.
  */
 export function spawnSubprocess(spec: SubprocessSpawnSpec, internals: SpawnInternals = {}): SubprocessHandle {
+  if (!Number.isFinite(spec.graceMs) || spec.graceMs <= 0 || spec.graceMs > MAX_TIMER_DELAY_MS) {
+    throw new Error(`subprocess graceMs must be a positive finite number no greater than ${MAX_TIMER_DELAY_MS}`)
+  }
   const spillDir = internals.spillDir ?? privateSpillDir()
   const platform = internals.platform ?? process.platform
   const taskkill = internals.taskkill ?? taskkillProcessTree
@@ -354,7 +359,9 @@ export function spawnSubprocess(spec: SubprocessSpawnSpec, internals: SpawnInter
   const stdoutCollector = collectStream(outMode, child.stdout, 'stdout')
   const stderrCollector = collectStream(errMode, child.stderr, 'stderr')
 
-  let graceTimer: NodeJS.Timeout | undefined
+  let graceTimer: ReturnType<typeof setTimeout> | undefined
+  let treeExitObserved = false
+  let treeExitObservation: Promise<void> | undefined
   let settled = false
 
   // Failed spawns use pid -1 so signalling remains a no-op.
@@ -362,6 +369,9 @@ export function spawnSubprocess(spec: SubprocessSpawnSpec, internals: SpawnInter
 
   /** Whether the detached tree's root (or POSIX group) is still alive. */
   const treeAlive = (): boolean => {
+    /* v8 ignore next -- only a timer callback already queued when the observer settles can enter here;
+       the guard is the final defense against probing an id after its tree was confirmed absent. */
+    if (treeExitObserved) return false
     if (pid <= 0) return false
     if (platform === 'win32') {
       // Windows has no group-liveness probe; the direct child's exit is the
@@ -389,19 +399,40 @@ export function spawnSubprocess(spec: SubprocessSpawnSpec, internals: SpawnInter
     }
   }
 
+  /**
+   * Start or reuse the handle's single whole-tree exit observer. The first
+   * confirmed absence is a permanent no-more-signals boundary: it cancels a
+   * pending escalation before this process-group id can be reused.
+   */
+  const observeTreeExit = (): Promise<void> => {
+    treeExitObservation ??= (async () => {
+      while (treeAlive()) await sleepTick()
+      treeExitObserved = true
+      if (graceTimer !== undefined) clearTimeout(graceTimer)
+      graceTimer = undefined
+    })()
+    return treeExitObservation
+  }
+
   // The escalation's tier primitive (not on the handle — terminate() is the
   // only consumer-facing termination verb). Guards on TREE liveness, not
   // outcome settlement: a TERM-trapping helper can outlive the settled direct
   // child and must stay signalable, while a fully-dead tree (possible pid
   // reuse) must not be re-signalled by a later tier.
   const kill = (sig: NodeJS.Signals): void => {
+    /* v8 ignore next -- the shared exit observer cancels the ordinary dead-tree timer;
+       this remains the timer/death race guard and cannot be staged deterministically. */
     if (!treeAlive()) return
     signalTree(platform, pid, sig, child, taskkill)
   }
 
   const terminate = (): void => {
-    if (graceTimer !== undefined) return // escalation already in flight
-    if (!treeAlive()) return
+    if (treeExitObserved || graceTimer !== undefined) return
+    // Observe from the first termination tier onward, even when inherited
+    // pipes delay `done` and no consumer has begun its own teardown wait.
+    void observeTreeExit()
+    // oxlint-disable-next-line typescript/no-unnecessary-condition -- observer can record absence before its first await.
+    if (treeExitObserved) return
     kill('SIGTERM')
     // The escalation must survive direct-child settlement — the leader dying
     // does not mean the tree died — so settle does not clear this timer, and
@@ -423,7 +454,7 @@ export function spawnSubprocess(spec: SubprocessSpawnSpec, internals: SpawnInter
   }
 
   const done = new Promise<SubprocessOutcome>((resolve, reject) => {
-    let pipeDrainTimer: NodeJS.Timeout | undefined
+    let pipeDrainTimer: ReturnType<typeof setTimeout> | undefined
     const settle = (exitCode: number | null, signal: NodeJS.Signals | null): void => {
       if (settled) return
       settled = true
@@ -446,7 +477,9 @@ export function spawnSubprocess(spec: SubprocessSpawnSpec, internals: SpawnInter
       // A surviving descendant that inherited a pipe must not hold the
       // outcome open indefinitely: after exit, the same bounded grace that
       // governs kills also bounds the close wait.
-      pipeDrainTimer = setTimeout(() => { settle(exitCode, signal) }, spec.graceMs)
+      pipeDrainTimer = setTimeout(() => {
+        settle(exitCode, signal)
+      }, spec.graceMs)
     })
     child.on('close', settle)
     function cleanup(): void {
@@ -458,11 +491,23 @@ export function spawnSubprocess(spec: SubprocessSpawnSpec, internals: SpawnInter
   })
 
   const waitForExit = async (signal?: AbortSignal): Promise<boolean> => {
-    while (treeAlive()) {
-      if (signal?.aborted) return false
-      await sleepTick()
+    const observed = observeTreeExit()
+    if (treeExitObserved) return true
+    if (signal?.aborted) return false
+    if (signal === undefined) {
+      await observed
+      return true
+    }
+    const aborted = Promise.withResolvers<boolean>()
+    const onAbort = (): void => { aborted.resolve(false) }
+    signal.addEventListener('abort', onAbort, { once: true })
+    /* v8 ignore next -- closes the event-loop race between the preceding aborted check and listener registration. */
+    if (signal.aborted) onAbort()
+    try {
+      return await Promise.race([observed.then(() => true), aborted.promise])
+    } finally {
+      signal.removeEventListener('abort', onAbort)
     }
-    return true
   }
 
   return {

packages/subprocess/subprocess-local/tests/spawn.spec.ts

@@ -280,18 +280,18 @@ describe('spawnSubprocess', () => {
 
   it('does not wait for a Linux group that has only zombie members', async () => {
     const pidFile = join(spillDir, `zombie-group-${Date.now()}.pid`)
-    let hasLiveMembers = false
     const running = spawnSubprocess(spec(`sleep 60 & echo $! > ${pidFile}; echo leader-done`, { graceMs: 100 }), {
       platform: 'linux',
-      linuxProcessGroupHasLiveMembers: () => hasLiveMembers,
+      linuxProcessGroupHasLiveMembers: () => false,
     })
     const descendant = await waitForPidFile(pidFile)
     try {
       await running.done
       await expect(running.waitForExit()).resolves.toBe(true)
     } finally {
-      hasLiveMembers = true
-      running.terminate()
+      // The confirmed-absent verdict is a permanent no-more-signals boundary,
+      // so terminate() must stay inert here; reap the live survivor directly.
+      process.kill(descendant, 'SIGKILL')
       await waitGone(descendant)
     }
   })