fix(settings): keep copied skill commands bare for POSIX-family Windows shells (#11599)

The cmd.exe npx preflight added in #10453 silently no-ops when pasted
into Git Bash: MSYS rewrites the leading /d /s /c switches into drive
paths, so cmd.exe starts an interactive session and never runs the
payload. Skip the wrapper when the configured Windows shell resolves to
the posix family, matching the shell the copied command actually lands
in.

src/renderer/src/components/settings/CliSkillRuntimeSetup.test.tsx

@@ -243,6 +243,55 @@ describe('CliSkillRuntimeSetup runtime helpers', () => {
     }
   })
 
+  it('skips the Windows preflight when the configured Windows shell is POSIX-family', () => {
+    const installCommand = buildAgentFeatureSkillInstallCommand(['orchestration'])
+    const windowsHost = { runtime: 'host', label: 'Windows' } as const
+    const previous = useAppStore.getState()
+
+    try {
+      // MSYS rewrites cmd.exe's leading /d /s /c switches into drive paths, so
+      // the copied command must stay bare for a Git Bash / wsl.exe paste target.
+      for (const terminalWindowsShell of ['git-bash', 'C:\\Program Files\\Git\\bin\\bash.exe']) {
+        useAppStore.setState({
+          settings: { ...getDefaultSettings('/tmp'), terminalWindowsShell }
+        })
+        expect(buildSkillCommandForRuntime(installCommand, windowsHost, 'win32')).toBe(
+          installCommand
+        )
+      }
+
+      // cmd-family shells still need the preflight wrapper.
+      useAppStore.setState({
+        settings: { ...getDefaultSettings('/tmp'), terminalWindowsShell: 'cmd.exe' }
+      })
+      expect(buildSkillCommandForRuntime(installCommand, windowsHost, 'win32')).toBe(
+        `${windowsNpxPreflightPrefix}${windowsNpxGuidance}) else (${installCommand})"`
+      )
+    } finally {
+      useAppStore.setState({ settings: previous.settings })
+    }
+  })
+
+  it('keeps the bare reinstall rewrite for POSIX-family Windows skill updates', () => {
+    const installCommand = buildAgentFeatureSkillInstallCommand(['orchestration'])
+    const previous = useAppStore.getState()
+    useAppStore.setState({
+      settings: { ...getDefaultSettings('/tmp'), terminalWindowsShell: 'git-bash' }
+    })
+
+    try {
+      expect(
+        buildSkillCommandForRuntime(
+          'npx skills update orchestration --global',
+          { runtime: 'host', label: 'Windows' },
+          'win32'
+        )
+      ).toBe(installCommand)
+    } finally {
+      useAppStore.setState({ settings: previous.settings })
+    }
+  })
+
   it('does not wrap unrelated Windows host commands', () => {
     expect(
       buildSkillCommandForRuntime(

src/renderer/src/components/settings/CliSkillRuntimeSetup.tsx

@@ -8,6 +8,7 @@ import {
   quotePowerShellNativeArgument
 } from '../../../../shared/powershell-native-argument'
 import { buildWslLoginShellCommand } from '../../../../shared/wsl-login-shell-command'
+import { resolveWindowsShellStartupFamily } from '../../../../shared/windows-terminal-shell'
 import { getProjectAgentSkillTerminalShellOverride } from '@/lib/project-skill-runtime'
 import { useAppStore } from '@/store'
 import { buildAgentFeatureSkillInstallCommand } from '../../../../shared/agent-feature-install-commands'
@@ -136,6 +137,10 @@ function wrapWindowsSkillCommandWithNpxPrerequisite(
     // Why: skill setup terminals spawn on the focused runtime environment, so a
     // Windows client must not hand a cmd.exe command to a remote host.
     isRemoteRuntimeEnvironmentFocused() ||
+    // Why: the copied command lands in the user's configured shell, and MSYS
+    // shells rewrite cmd.exe's leading /d /s /c switches into drive paths,
+    // starting an interactive cmd session instead of running the payload.
+    isPosixFamilyWindowsShellConfigured() ||
     !/^npx\s+skills\s+(?:add|update)\b/i.test(trimmedCommand)
   ) {
     return command
@@ -149,6 +154,13 @@ function wrapWindowsSkillCommandWithNpxPrerequisite(
   return `cmd.exe /d /s /c "where.exe npx >nul 2>nul & if errorlevel 1 (${missingNpxGuidance}) else (${trimmedCommand})"`
 }
 
+function isPosixFamilyWindowsShellConfigured(): boolean {
+  return (
+    resolveWindowsShellStartupFamily(useAppStore.getState().settings?.terminalWindowsShell) ===
+    'posix'
+  )
+}
+
 function isRemoteRuntimeEnvironmentFocused(): boolean {
   // Why: the terminal router also weighs how many environments are saved, but
   // that slice has no subscriber here. Read only the focused id, which every