docs(pwsh): scope the encoding claim, document the PATH probe and preamble limitation, and fix catalog requires lists

packages/bash/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/bash/pwsh-local/README.md
-README.md: 430419cc34added1e983e3fc119cfeb1eebb6829
-README.zh.md: 4a1246a31a22143d6a260cc7b3024dc490f19b7f
+README.md: bb5d941b0cc98fb14e0b47d5bbe0bffb5192edd8
+README.zh.md: efd8aac2b8766d1082b85905fce9867151b77310

packages/bash/pwsh-local/README.md

@@ -28,7 +28,7 @@ The package root exports the default and named `PwshLocalExecutor` plugin, its `
 The Windows counterpart of `dsh-bash-local`, deliberately mirroring its semantics call-for-call:
 
 - **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.
-- **UTF-8 I/O pinned** — every command runs with `[Console]::OutputEncoding` and `$OutputEncoding` set to UTF-8 first, so the Windows PowerShell 5.1 fallback (or any host whose console code page is not UTF-8) cannot garble non-ASCII output: the subprocess collector decodes bytes as UTF-8. pwsh 7 defaults to UTF-8 and is unaffected.
+- **UTF-8 output pinned** — every command runs with `[Console]::OutputEncoding` and `$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)` and happens once at construction.
 - **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`. 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 `BashExecRequest.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.
@@ -50,5 +50,6 @@ No direct invalidation; the named consumer owns any request-prefix changes.
 - **The command string is PowerShell text** — the `-Command` domain has no shell-quoting layer, but a model-facing command is parsed by PowerShell itself, so PowerShell syntax errors are command failures, not launch failures.
 - **A background spawn-failure note is single-delivery** — the subprocess service buffers no output for a process that never ran, so the executor injects `spawn failed: …` into exactly one `readOutput()` delta; a reader that discards that delta cannot recover it.
 - **Windows termination reports no signal** — a force-killed process settles as exit 1 with `signal: null`, so signal-based status classification (POSIX `killed`) does not apply on Windows; `kill()`-initiated stops still stamp `killed` directly.
+- **The encoding preamble precedes the command** — PowerShell requires `param(...)` and `using namespace`/`using assembly` statements at the very top of a script, so a command whose first statement is one of those cannot run under the UTF-8 output preamble; prefix such scripts with a no-op statement (or `& { … }`) first.
 
 Scrub-heuristic and spill-retention caveats live with [`dsh-subprocess-local`](../../subprocess/subprocess-local/README.md), which owns those mechanics.

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

@@ -28,7 +28,7 @@
 作为 `dsh-bash-local` 的 Windows 对应物，逐调用地镜像其语义：
 
 - **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。
-- **UTF-8 I/O 固定**——每条命令都先以 UTF-8 设置 `[Console]::OutputEncoding` 与 `$OutputEncoding`，因此 Windows PowerShell 5.1 兜底（或任何控制台代码页非 UTF-8 的主机）不会破坏非 ASCII 输出：subprocess collector 以 UTF-8 解码字节。pwsh 7 默认为 UTF-8，不受影响。
+- **UTF-8 输出固定**——每条命令都先以 UTF-8 设置 `[Console]::OutputEncoding` 与 `$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 collector 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，在构造时执行一次。
 - **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`。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 `BashExecRequest.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 融合配置夹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，因此基于信号的实情（`signal`、`killed` 状态）在那里仅限 POSIX；超时/取消分类与平台无关。
@@ -50,5 +50,6 @@
 - **命令字符串是 PowerShell 文本**——`-Command` 域没有 shell 引号层，但面向模型的命令由 PowerShell 自己解析，因此 PowerShell 语法错误是命令失败，而非启动失败。
 - **后台 spawn 失败提示只投递一次**——subprocess 服务不会为从未运行的进程缓冲输出，因此执行器只把 `spawn failed: …` 注入一次 `readOutput()` 增量；丢弃该增量的读取方无法恢复它。
 - **Windows 终止不报告信号**——被强制终止的进程以退出码 1、`signal: null` 结束，因此基于信号的状态分类（POSIX `killed`）在 Windows 上不适用；`kill()` 发起的停止仍会直接盖上 `killed`。
+- **编码 preamble 位于命令之前**——PowerShell 要求 `param(...)` 与 `using namespace`/`using assembly` 语句位于脚本最顶部，因此以其中一种开头的命令无法在 UTF-8 输出 preamble 下运行；请先用无操作语句（或 `& { … }`）开头。
 
 清理启发式与 spill 保留的注意事项由 [`dsh-subprocess-local`](../../subprocess/subprocess-local/README.md) 持有，它拥有这些机制。

packages/bash/pwsh-local/src/index.ts

@@ -35,7 +35,7 @@ export const ENV_OVERRIDES = {
 } as const
 
 /**
- * UTF-8 I/O pinning prepended to every command. The subprocess collector
+ * UTF-8 output pinning prepended to every command. The subprocess collector
  * decodes output bytes as UTF-8, but Windows PowerShell 5.1 (the last-resort
  * executable fallback) writes the console/OEM code page by default, which
  * garbles non-ASCII output; pwsh 7 defaults to UTF-8 and is unaffected. The
@@ -67,8 +67,9 @@ export interface Config {
   graceMs?: number
   /**
    * Explicit pwsh executable. When omitted, well-known Windows install
-   * locations are probed first (PowerShell 7, then Windows PowerShell 5.1),
-   * falling back to a bare `pwsh` resolved through PATH.
+   * locations and PATH entries are probed in order (PowerShell 7 install,
+   * PATH entries such as the Microsoft Store install, then Windows
+   * PowerShell 5.1), falling back to a bare `pwsh` resolved through PATH.
    */
   pwshPath?: string
 }