Paste from GNOME Text Editor still fails on GNOME Wayland in 1.0.57

### Describe the bug

On GNOME Wayland, pasting text copied from **GNOME Text Editor** directly into the Copilot CLI prompt still fails on **1.0.57**.

A notable workaround is that if I first paste the same content into a normal terminal, then copy it again from the terminal, it can be pasted into Copilot CLI successfully.

This strongly suggests Copilot CLI is still mishandling clipboard content/type probing from editor-originated clipboard data on GNOME Wayland, while terminal re-copy reduces it to a simpler plain-text clipboard payload that works.

### Affected version

GitHub Copilot CLI 1.0.57

### Steps to reproduce the behavior

1. Use Ubuntu GNOME on Wayland.
2. Open **GNOME Text Editor**.
3. Copy some plain text from the editor.
4. Open `copilot` inside **GNOME Terminal**.
5. Try pasting into the Copilot CLI prompt.
6. Observe that paste does not work correctly.
7. As a workaround, paste the same text into a normal terminal first, copy it again from that terminal, then paste into Copilot CLI.
8. Observe that the terminal-recopied text pastes successfully into Copilot CLI.

### Expected behavior

Text copied from a normal desktop text editor should paste into the Copilot CLI prompt on GNOME Wayland without needing a terminal re-copy workaround.

### Additional context

Environment:

- OS: Ubuntu (Wayland session)
- Desktop: GNOME / Mutter
- Terminal: GNOME Terminal
- Editor: GNOME Text Editor
- Copilot CLI: 1.0.57

Relevant log evidence from `~/.copilot/logs/process-*.log`:

```text
Failed to get clipboard attachment file path: Error: Failed to get files: Failed to query MIME types: A required Wayland protocol (ext-data-control, or wlr-data-control version 1) is not supported by the compositor
Failed to write clipboard image to disk: Error: Failed to get image: Failed to query MIME types: A required Wayland protocol (ext-data-control, or wlr-data-control version 1) is not supported by the compositor
```

This appears related to the earlier GNOME Wayland paste issue in #3414, but the problem is still reproducible in 1.0.57 with a concrete editor-to-Copilot repro path.

The key symptom difference worth calling out is:

- **Direct editor -> Copilot CLI paste fails**
- **Editor -> terminal -> recopy -> Copilot CLI paste works**

That suggests the remaining bug is not just generic paste failure, but handling of clipboard metadata/MIME types from editor-provided clipboard content under GNOME Wayland.

Reproduce the direct editor-to-Copilot paste and terminal-recopy workaround in GNOME Wayland, then inspect ~/.copilot/logs/process-*.log for the clipboard errors. Read the earlier GNOME Wayland issue #3414 and trace the Copilot CLI prompt's clipboard handling. Done when text copied from GNOME Text Editor pastes directly into the prompt without the terminal workaround.

索引モデルが issue の本文から書いたものです。