fix(pwsh): accept link-shaped candidates and sync the README contract

packages/shell/pwsh-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/shell/pwsh-local/README.md
-README.md: cfb58b569022bca11d18c196e0bce104247e4c81
-README.zh.md: 9393c5d210743d8423457f2d7df5900c1e0df182
+README.md: 2eccc59b919d1f729eef52a42581f4da0f1d9e60
+README.zh.md: a03f80343711a1471bc96017e23476a3253ec46c

packages/shell/pwsh-local/README.md

@@ -30,7 +30,7 @@ The Windows counterpart of `dsh-bash-local`, deliberately mirroring its semantic
 - **Spawn per call, no shell state** — every call is a fresh non-interactive `pwsh -Command` (deterministic; no profile files). The `-NoLogo -NoProfile -NonInteractive` flags disable startup banners, profile loading, and prompts that would garble tool output.
 - **The composition entry is a layer, not the last word** — when a settings provider is composed, this executor registers the capability's [`bash` namespace](../shell/README.md) with the entry above as its base, so a user section in `settings.yaml` layers over it and the next command runs with the new budgets. The namespace is shared with the POSIX family because a host composes exactly one provider of `ctx.shell`; a document written on either platform keeps resolving on the other. Values the schema cannot judge (positive and finite, the `graceMs` timer bound) are refused at the write, leaving the running executor on its last good section.
 - **UTF-8 output pinned** — every command runs with `[Console]::OutputEncoding` and `$OutputEncoding` set to UTF-8 first, so the Windows PowerShell 5.1 fallback (or any host whose console code page is not UTF-8) cannot garble non-ASCII output: the subprocess collector decodes bytes as UTF-8. Input encoding is left at the host default; pwsh 7 defaults to UTF-8 and is unaffected.
-- **Executable resolution** — `resolvePwshPath` prefers an explicit `pwshPath`, then on Windows probes PowerShell 7's install location, every PATH entry (Microsoft Store installs; surrounding quotes stripped), and Windows PowerShell 5.1 as a legacy last resort, checking `existsSync` on each; elsewhere it falls back to a bare `pwsh` resolved through PATH. Resolution is a pure function of `(configured, env, platform)`; it runs at construction and again only when a stored `pwshPath` differs from the one the current executable was resolved from, so an unrelated settings change never re-probes the filesystem.
+- **Executable resolution** — `resolvePwshPath` prefers an explicit `pwshPath`, then on Windows probes PowerShell 7's install location, every PATH entry (Microsoft Store installs; surrounding quotes stripped), and Windows PowerShell 5.1 as a legacy last resort, checking each candidate with an lstat probe that accepts a real file or a link-shaped reparse point (a Store app execution alias stat-fails against its target's ACL, but lstat sees the alias itself); elsewhere it falls back to a bare `pwsh` resolved through PATH. Resolution is a pure function of `(configured, env, platform)`; it runs at construction and again only when a stored `pwshPath` differs from the one the current executable was resolved from, so an unrelated settings change never re-probes the filesystem.
 - **Configured budgets over managed groups** — `resolve()` fills `workdir`/`timeoutMs`/`stdoutMaxBytes` from config, and every spawn hands the service explicit byte caps, spill cap, and `graceMs`. The grace must be positive, finite, and no greater than [`MAX_TIMER_DELAY_MS`](../../util/timeout/README.md), so Node can represent it with one timer. Tree termination (taskkill on Windows, process-group signals on POSIX), the post-exit pipe-drain grace, tail-keep truncation, and bounded spill files are [`dsh-subprocess-local`](../../subprocess/subprocess-local/README.md) mechanics. A foreground `ShellExecRequest.stdoutMaxBytes` can raise stdout's capture budget for one trusted caller; stderr and background runs still use `maxOutputBytes`.
 - **Timeout and cancel classification** — `run()` fuses its config-clamped timeout with the caller's signal through one deadline; only the executor's own timeout reports `timedOut`, an upstream cancel reports `aborted`, and a self-terminated command reports neither ([timeout-library Agent Note](../../../.agents/notes/implemented/architecture/2026-07-06-timeout-deadline-library.md)). Windows reports forced termination as exit 1 without a signal, so signal-stamped facts (`signal`, `killed` status) are POSIX-only there; the timeout/abort classification is platform-independent.
 - **Model-friendly terminal env** — `NO_COLOR=1 PAGER=cat GIT_PAGER=cat` (no `TERM=dumb`: that is a POSIX concept; `NO_COLOR` is honored by modern PowerShell renderers) merged as ordinary env under the service's credential scrub and `DSH_*` channel rules; an explicit caller entry still wins.

packages/shell/pwsh-local/README.zh.md

@@ -30,7 +30,7 @@
 - **每次调用新建进程，无 shell 状态**——每次调用都是全新的非交互 `pwsh -Command`（确定性；不加载 profile 文件）。`-NoLogo -NoProfile -NonInteractive` 关闭启动横幅、profile 加载与会干扰工具输出的提示符。
 - **组装条目是一层，而不是最终值**——当组装中存在 settings 提供方时，本执行器以上面的条目为 base 注册该能力的 [`bash` 命名空间](../shell/README.md)，因此 `settings.yaml` 中的用户段会叠加其上，下一条命令即按新预算运行。该命名空间与 POSIX 家族共用，因为一个宿主只组装一个 `ctx.shell` 提供方；在任一平台写下的文档在另一平台仍能解析。schema 无法判定的值（正有限、`graceMs` 的定时器上界）会在写入时被拒绝，运行中的执行器保持它最后一份可用的段。
 - **UTF-8 输出固定**——每条命令都先以 UTF-8 设置 `[Console]::OutputEncoding` 与 `$OutputEncoding`，因此 Windows PowerShell 5.1 兜底（或任何控制台代码页非 UTF-8 的主机）不会破坏非 ASCII 输出：subprocess 收集器以 UTF-8 解码字节。输入编码保持宿主默认；pwsh 7 默认为 UTF-8，不受影响。
-- **可执行文件解析**——`resolvePwshPath` 优先显式 `pwshPath`，然后在 Windows 上依次探测 PowerShell 7 安装位置、每个 PATH 条目（Microsoft Store 安装；剥离两端引号）以及作为遗留兜底的 Windows PowerShell 5.1，逐一检查 `existsSync`；其他平台回退为通过 PATH 解析的裸 `pwsh`。解析是 `(configured, env, platform)` 的纯函数；它在构造时执行，此后仅当存储的 `pwshPath` 与当前可执行文件所依据的值不同才再次执行，因此无关的设置变更绝不会重新探测文件系统。
+- **可执行文件解析**——`resolvePwshPath` 优先显式 `pwshPath`，然后在 Windows 上依次探测 PowerShell 7 安装位置、每个 PATH 条目（Microsoft Store 安装；剥离两端引号）以及作为遗留兜底的 Windows PowerShell 5.1，逐一用 lstat 探测检查（接受真实文件或链接形态的重解析点：Store 的 app execution alias 对其目标 stat 会因 ACL 失败，但 lstat 能看到别名本身）；其他平台回退为通过 PATH 解析的裸 `pwsh`。解析是 `(configured, env, platform)` 的纯函数；它在构造时执行，此后仅当存储的 `pwshPath` 与当前可执行文件所依据的值不同才再次执行，因此无关的设置变更绝不会重新探测文件系统。
 - **受管进程组之上的配置预算**——`resolve()` 从配置填充 `workdir`/`timeoutMs`/`stdoutMaxBytes`，每次 spawn 都向服务提供显式字节上限、spill 上限与 `graceMs`。该宽限期须为正有限值，且不得大于 [`MAX_TIMER_DELAY_MS`](../../util/timeout/README.md)，这样 Node 就能用一个定时器表示它。进程树终止（Windows 用 taskkill，POSIX 用进程组信号）、退出后管道排空宽限、保尾截断与有界 spill 文件是 [`dsh-subprocess-local`](../../subprocess/subprocess-local/README.md) 的机制。前台 `ShellExecRequest.stdoutMaxBytes` 可为单个受信调用方提高 stdout 捕获预算；stderr 与后台运行仍使用 `maxOutputBytes`。
 - **超时与取消分类**——`run()` 通过一个 deadline 融合按配置上限截取的超时与调用方信号；只有执行器自身超时报告 `timedOut`，上游取消报告 `aborted`，自我终止的命令两者都不报告（见 [timeout 库 Agent Note](../../../.agents/notes/implemented/architecture/2026-07-06-timeout-deadline-library.md)）。Windows 将强制终止报告为退出码 1 且无信号，因此带信号标记的事实（`signal`、`killed` 状态）在那里仅限 POSIX；超时/取消分类与平台无关。
 - **面向模型的终端环境**——`NO_COLOR=1 PAGER=cat GIT_PAGER=cat`（没有 `TERM=dumb`：那是 POSIX 概念；现代 PowerShell 渲染器遵循 `NO_COLOR`），作为普通 env 在服务的凭据清理与 `DSH_*` 通道规则之下合并；显式调用方条目仍然优先。

packages/shell/pwsh-local/src/resolve.ts

@@ -8,7 +8,7 @@
  * @module @deepseek-ai/dsh-pwsh-local/resolve
  */
 
-import { existsSync, lstatSync } from 'node:fs'
+import { lstatSync } from 'node:fs'
 import { join } from 'node:path'
 
 /**
@@ -36,15 +36,21 @@ export function candidatePwshPaths(env: NodeJS.ProcessEnv = process.env): string
   return candidates
 }
 
-/** Whether a candidate can be spawned: a real file or a link-shaped reparse point. */
+/**
+ * Whether a candidate can be spawned. lstat opens the entry itself instead of
+ * following reparse points, so it sees the Store app execution alias where
+ * stat hits the target's ACL (EACCES); Node reports that alias as a symlink
+ * on current releases and as a plain file on older ones, and CreateProcess
+ * resolves either shape. A real directory never matches.
+ */
 function candidateExists(candidate: string): boolean {
-  if (existsSync(candidate)) return true
-  // Microsoft Store app execution aliases are reparse points whose target
-  // ACL refuses stat(), so existsSync misses them; lstat sees the link
-  // itself and CreateProcess resolves it when the executor spawns.
   try {
-    return lstatSync(candidate).isSymbolicLink()
+    const stat = lstatSync(candidate)
+    return stat.isFile() || stat.isSymbolicLink()
   } catch {
+    // ENOENT (the candidate vanished between listing and probing) is the only
+    // expected failure; any other error names an unspawnable path, so false
+    // is the safe answer for it too.
     return false
   }
 }

packages/shell/pwsh-local/tests/executor.spec.ts

@@ -138,6 +138,17 @@ describe('resolvePwshPath and candidatePwshPaths (pure, every platform)', () =>
     expect(resolvePwshPath(undefined, { ProgramFiles: join(dir, 'missing'), PATH: store }, 'win32'))
       .toBe(link)
   })
+
+  it('skips a directory candidate and falls through to the PATH-resolution default', () => {
+    const dir = mkdtempSync(join(tmpdir(), 'dsh-pwsh-resolve-dir-'))
+    const store = join(dir, 'store')
+    mkdirSync(join(store, 'pwsh.exe'), { recursive: true })
+    expect(resolvePwshPath(undefined, {
+      ProgramFiles: join(dir, 'missing'),
+      PATH: store,
+      SystemRoot: join(dir, 'no-windows'),
+    }, 'win32')).toBe('pwsh')
+  })
 })
 
 describe('spawn construction (pure, every platform)', () => {