Stealth mode does not trigger on clipboard changes in WSLg

Hi,

I’m experiencing a problem with the `cht.sh` command-line client’s stealth mode while running on WSL2 with WSLg. Clipboard polling works (I can use `xsel --clipboard` and receive Windows clipboard contents), and manual queries in `cht.sh` work as expected. However, when I enter `stealth` mode, copying text in Windows does not trigger any query or response in the terminal. There are no error messages displayed.

#### Steps to reproduce:
1. Run WSL2 with WSLg on Windows 11.
2. Run the latest `cht.sh` script:
```sh
curl https://cht.sh/:cht.sh > ~/cht.sh
chmod +x ~/cht.sh
~/cht.sh --shell
```
3. Enter `stealth` mode at the `cht.sh>` prompt.
4. Copy a short programming query (e.g., `python list comprehension`) in any Windows application.
5. Observe that nothing happens in the terminal (no query triggered, no output).
6. Confirm that `xsel --clipboard` in WSL shows the correct clipboard contents.

#### What I expected:
When I copy a short query in Windows, `cht.sh` should automatically fetch and display the answer in stealth mode.

#### What actually happens:
Nothing happens—no query is triggered, and the terminal remains idle. Manual queries work. No errors are shown.

#### Additional info:
- WSL version: 2.5.9.0
- Kernel version: 6.6.87.2-1
- WSLg version: 1.0.66
- Windows version: 10.0.26120.4452
- Default shell: bash
- Python version: 3.12.3
- `cht.sh` is up to date as of 2025-06-25

First line of ~/cht.sh:
```bash
#!/bin/bash
```

#### Troubleshooting attempted:
- Verified clipboard polling in Python (works as expected)
- Installed both `xsel` and `xclip`
- Tried running `cht.sh` in a clean shell environment
- No custom `.bashrc` or `.zshrc` interfering
- No error output observed

Start by running ~/cht.sh --shell, entering stealth mode, and confirming that xsel --clipboard sees the Windows clipboard. Then inspect the stealth-mode and clipboard-polling paths in ~/cht.sh; done means a clipboard change in WSLg triggers the query and displays its response while manual queries continue to work.

Written by the indexing model from the issue text.