Merge remote-tracking branch 'origin/doc/host-client-group-readmes' into feat/directory-picker

# Conflicts:
#	packages/client/connection/src/client/fixture.ts
#	packages/client/connection/tests/fake-api.ts
#	packages/client/runtime/src/client/workspaces/service.ts
#	packages/client/runtime/tests/fake-api.ts
#	packages/client/ui-workspace/src/client/WorkspaceBrowser.tsx
#	packages/client/ui-workspace/src/client/WorkspacePicker.tsx
#	packages/client/ui-workspace/tests/workspace-picker.spec.tsx
#	packages/host/apiproxy/README.i18n.yaml
#	packages/host/apiproxy/src/api-proxy.ts
#	packages/host/apiproxy/src/api/host.schema.ts
#	packages/host/apiproxy/src/api/host.ts
#	packages/host/apiproxy/src/api/rpc-map.ts
#	packages/host/apiproxy/src/fetch/client.ts
#	packages/host/apiproxy/src/fetch/handler.ts
#	packages/host/apiproxy/tests/api-proxy-workspace.spec.ts
#	packages/host/apiproxy/tests/client-handler.spec.ts
#	packages/host/apiproxy/tests/fetch-carrier.spec.ts

packages/host/directory-picker-native/src/native-picker.ts

@@ -1,13 +1,9 @@
 /** Cross-platform native single-directory chooser behind the dialog backend's capability. */
 
-import { execFile } from 'node:child_process'
+import { runNativeCommand, type NativeCommandRunner } from './native-command.ts'
 
 /** Testable command boundary; native implementations never invoke a shell. */
-export type DirectoryPickerRunner = (
-  command: string,
-  args: readonly string[],
-  signal: AbortSignal,
-) => Promise<{ stdout: string; stderr: string }>
+export type DirectoryPickerRunner = NativeCommandRunner
 
 /** Injectable platform facts for deterministic adapter tests. */
 export interface DirectoryPickerInternals {
@@ -15,27 +11,6 @@ export interface DirectoryPickerInternals {
   run?: DirectoryPickerRunner
 }
 
-const runCommand: DirectoryPickerRunner = (command, args, signal) =>
-  new Promise((resolve, reject) => {
-    execFile(
-      command,
-      [...args],
-      { encoding: 'utf8', signal, windowsHide: true },
-      (error, stdout, stderr) => {
-        if (error !== null) {
-          const failure = Object.assign(new Error(error.message, { cause: error }), {
-            code: error.code,
-            stdout,
-            stderr,
-          })
-          reject(failure)
-          return
-        }
-        resolve({ stdout, stderr })
-      },
-    )
-  })
-
 function outputPath(stdout: string): string | null {
   const path = stdout.replace(/[\r\n]+$/, '')
   return path === '' ? null : path
@@ -72,7 +47,7 @@ export async function pickNativeDirectory(
   internals: DirectoryPickerInternals = {},
 ): Promise<string | null> {
   const platform = internals.platform ?? process.platform
-  const run = internals.run ?? runCommand
+  const run = internals.run ?? runNativeCommand
 
   if (platform === 'darwin') {
     try {