feat(pwsh): add the pwsh-local executor and the pwsh tool

Windows-native execution foundation: PwshLocalExecutor implements the bash
executor seam over ctx.subprocess (pwsh -NoLogo -NoProfile -NonInteractive
-Command, one argv element, no quoting layer; resolvePwshPath probes
PowerShell 7 / PATH / Windows PowerShell 5.1 as a pure function), and
tool-pwsh is the minimal PowerShell-dialect model-facing tool over ctx.bash
(foreground only, managed DSH_* env, timeout/signal/exit markers, terminal
and generic presenters). Both packages carry full suites (real pwsh,
self-skipping without it) at per-file 100% coverage; vitest's Windows
exclusion narrows from packages/bash/* to the bash-requiring packages so the
pwsh suites run natively on Windows too. The CLI gains the workspace deps
and tsconfig projects without mounting either plugin; the Windows-default
roadmap is recorded as a proposed Agent Note.

docs/tool-catalog.md

@@ -19,6 +19,7 @@ This table connects model-visible tool names to the plugin package and service s
 | `@deepseek-ai/dsh-tools` | `run_code` | `ctx.tools`, `ctx.codeRuntime (execution time)`, `ctx.systemPrompt` | `tool/call`, `one tool/code-dispatch-start + tool/code-dispatch pair per bridged sub-call`, `tool/result` | - | Owned by the tool registry as a reserved transport outside filterable capability layers under `mode: code` / `mode: both` (see the Code Mode Agent Note). Under `code` it is the registry's only wire contribution; the other visible capabilities are declared in a generated TypeScript SDK section, and a program calls them through bindings scheduled under the native concurrency contract (submission-ordered starts and policy; concurrency-safe bodies overlap up to `maxParallelSubCalls`) that re-enter the complete guarded tool pipeline and link each nested execution to this outer result. |
 | `@deepseek-ai/dsh-plan-mode` | `exit_plan_mode` | `ctx.tools`, `ctx.systemPrompt`, `ctx.userInteraction (execution time, opportunistic)` | `tool/call`, `plan/mode inactive on an approved review`, `tool/result` | - | exit_plan_mode stays in the model-facing schema while planning is inactive so transitions add no tool-catalog churn on top of the plan-policy change. Its execute path rejects calls outside plan mode; in plan mode it presents the plan over the user-interaction seam (approve / keep planning with feedback), and approval logs plan mode inactive at the step boundary. |
 | `@deepseek-ai/dsh-tool-bash` | `bash` | `ctx.tools`, `ctx.bash`, `ctx.tasks at call time for run_in_background` | `tool/call`, `tool/result` | - | The bash tool is the model-facing consumer of the bash executor seam. A `run_in_background` run registers with the generic `ctx.tasks` runtime and is collected/stopped through the `task_*` tools from `@deepseek-ai/dsh-tool-tasks`; the `enableRunInBackground` config (default true) removes the parameter entirely when disabled. |
+| `@deepseek-ai/dsh-tool-pwsh` | `pwsh` | `ctx.tools`, `ctx.bash`, `ctx.systemPrompt` | `tool/call`, `tool/result` | - | The pwsh tool is the PowerShell-dialect consumer of the bash executor seam for Windows compositions (a PowerShell executor such as `@deepseek-ai/dsh-pwsh-local` backs `ctx.bash`); minimal by design — foreground only, no sandbox escalation, native `C:\...` paths and `$env:NAME` variables. |
 | `@deepseek-ai/dsh-tool-cordis` | `cordis_inspect`, `cordis_mount`, `cordis_unmount` | `ctx.tools` | `tool/call`, `tool/result`, `process-local temporary Plugin lifecycle` | - | Not in any shipped tree (a deliberate opt-in — temporary Plugin code reaches the real runtime, see .agents/notes/implemented/feature/2026-07-08-self-referential-cordis-toolset.md). Plugins created by cordis_mount may register ADDITIONAL model-visible tools until unmounted or DSH restarts; a full changed request header logs those tool-set changes. |
 | `@deepseek-ai/dsh-tool-bash-persistent` | `bash` | `ctx.tools`, `ctx.pty`, `an owning Agent at execution time` | `tool/call`, `PTY shell state`, `tool/result` | - | One owner-isolated persistent bash tool; deployment composition supplies the PTY backend and may override the model-facing environment description. |
 | `@deepseek-ai/dsh-tool-str-replace-editor` | `str_replace_editor` | `ctx.tools`, `ctx.fs` | `tool/call`, `fs/observed after successful file operations`, `tool/result` | - | Standalone view/create/unique literal replace/line insert tool over the filesystem seam; it composes with any shell or terminal surface. |
@@ -205,6 +206,44 @@ Source: [`packages/bash/tool-bash/src/index.ts`](../packages/bash/tool-bash/src/
 
 The bash tool is the model-facing consumer of the bash executor seam. A `run_in_background` run registers with the generic `ctx.tasks` runtime and is collected/stopped through the `task_*` tools from `@deepseek-ai/dsh-tool-tasks`; the `enableRunInBackground` config (default true) removes the parameter entirely when disabled.
 
+## `@deepseek-ai/dsh-tool-pwsh`
+
+### `pwsh`
+
+Execute a PowerShell command (`pwsh -Command`) and return its stdout/stderr. Each call runs in a fresh pwsh process: no state (cwd, variables, functions) persists between calls — pass `workdir` instead of using `cd`. Paths use native Windows form (`C:\...`); read environment variables with `$env:NAME`. Non-zero exits are reported as `[exit code: N]`. Long output is truncated to its tail; the full output is saved to a file whose path is reported when available.
+
+```json
+{
+  "type": "object",
+  "properties": {
+    "command": {
+      "type": "string",
+      "description": "The PowerShell command to execute."
+    },
+    "description": {
+      "type": "string",
+      "description": "Clear, concise description of what this command does in active voice, 5-10 words (shown in the UI). Examples: \"ls\" → \"List files in current directory\"; \"git status\" → \"Show working tree status\"; \"Get-Process\" → \"List running processes\"."
+    },
+    "timeoutMs": {
+      "type": "number",
+      "description": "Timeout in milliseconds. The executor applies its configured default and cap, and kills the command on expiry."
+    },
+    "workdir": {
+      "type": "string",
+      "description": "Working directory for this command. Defaults to the session workspace; a relative path is resolved against it."
+    }
+  },
+  "required": [
+    "command",
+    "description"
+  ]
+}
+```
+
+Source: [`packages/bash/tool-pwsh/src/index.ts`](../packages/bash/tool-pwsh/src/index.ts)
+
+The pwsh tool is the PowerShell-dialect consumer of the bash executor seam for Windows compositions (a PowerShell executor such as `@deepseek-ai/dsh-pwsh-local` backs `ctx.bash`); minimal by design — foreground only, no sandbox escalation, native `C:\...` paths and `$env:NAME` variables.
+
 ## `@deepseek-ai/dsh-tool-cordis`
 
 ### `cordis_inspect`