CmdPal: Fix crash on summon when UseLowLevelGlobalHotkey is enabled

[Copilot]

Summary of the Pull Request

Fixes RPC_E_CANTCALLOUT_ININPUTSYNCCALL (0x8001010D) crash when CmdPal is summoned via the low-level keyboard hook (UseLowLevelGlobalHotkey). The WH_KEYBOARD_LL hook fires on an input-synchronous thread; calling HandleSummon directly from it triggered HideWindow() → ShowWindow → WinUI COM calls, which COM forbids in that context.

PR Checklist

• Communication: I've discussed this with core contributors already. If the work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end-user-facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

MainWindow.xaml.cs — SetProcessCommand registration

The ProcessCommand delegate passed to KeyboardListener was a direct method reference, so HandleSummon ran synchronously on the hook thread. Wrapping it with DispatcherQueue.TryEnqueue posts the work to the UI thread's message queue, ensuring it executes after the hook callback returns:

// Before
_keyboardListener.SetProcessCommand(new CmdPalKeyboardService.ProcessCommand(HandleSummon));

// After
_keyboardListener.SetProcessCommand(new CmdPalKeyboardService.ProcessCommand(
    (id) => DispatcherQueue.TryEnqueue(() => HandleSummon(id))));

The WM_HOTKEY path (HotKeyPrc) is unaffected — it already runs on the UI thread's message pump.

Validation Steps Performed

• Code review and static analysis passed with no blocking issues.
• The fix is logically equivalent to the existing pattern used elsewhere in MainWindow (e.g. SettingsChangedHandler, DragCompletedMessage) where off-thread callbacks are marshalled to the UI thread via DispatcherQueue.TryEnqueue.

[Copilot]

Pull request overview

Fixes a crash when Command Palette is summoned via the low-level global hotkey (UseLowLevelGlobalHotkey) by ensuring the summon handler runs on the UI thread rather than directly on the WH_KEYBOARD_LL hook callback thread (which is an input-synchronous context and can’t safely perform WinUI/COM window operations).

Changes:

• Wrapes the KeyboardListener ProcessCommand callback to enqueue HandleSummon onto the window DispatcherQueue.
• Adds detailed inline documentation explaining the RPC_E_CANTCALLOUT_ININPUTSYNCCALL (0x8001010D) failure mode and why dispatching resolves it.