test(tui): cover same-volume cwd outside home

The existing /opt footer case reaches the ordinary outside-home return on POSIX, but Windows resolves it on the checkout drive while the user profile is on another drive. That exercises the cross-drive guard instead and leaves the same-volume fallback uncovered in Windows coverage.

Add the resolved parent of the home directory as a platform-neutral outside-home path. The case now covers the fallback on every host while retaining /opt to exercise the Windows cross-drive path, restoring per-file branch, statement, and line coverage without platform-specific expectations.

packages/ui/tui/tests/tui.spec.ts

@@ -1,5 +1,5 @@
 import { homedir } from 'node:os'
-import { join } from 'node:path'
+import { join, resolve } from 'node:path'
 import { describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import type { Terminal } from '@earendil-works/pi-tui'
@@ -361,6 +361,11 @@ describe('pi-tui chat lifecycle and transcript', () => {
     expect(unsetResult.terminal.output).toContain('cwd unset')
     await dispose(unsetResult)
 
+    const homeParent = resolve(home, '..')
+    const parentResult = await setup({ cwd: homeParent })
+    expect(parentResult.terminal.output).toContain(homeParent)
+    await dispose(parentResult)
+
     const outsideResult = await setup({ cwd: '/opt' })
     expect(outsideResult.terminal.output).toContain('/opt')
     await dispose(outsideResult)