Cannot type Polish characters (AltGr combinations) in Copilot CLI input on Windows

### Describe the bug

It is impossible to type characters that require the AltGr key (right Alt) in the Copilot CLI input field. This affects Polish characters: ą, ę, ó, ś, ź, ż, ć, ń, ł — and likely other languages using AltGr combinations

### Affected version

1.0.34

### Steps to reproduce the behavior

1. Open Copilot CLI on Windows
2. Try to type a Polish character using AltGr + letter (e.g., AltGr+A for ą, AltGr+L for ł)
3. Nothing is typed, or a wrong character/action is triggered

### Expected behavior

AltGr key combinations should produce the correct Unicode characters in the input field.

### Additional context

- OS: Windows
- Terminal: Windows Terminal / PowerShell

Reproduce the issue in Copilot CLI 1.0.34 using Windows Terminal or PowerShell with a Polish keyboard layout, then trace the CLI input handling for AltGr key combinations. Done means Polish characters such as ą and ł can be entered correctly without triggering an unintended character or action.

Written by the indexing model from the issue text.