1.0.34: mintty terminal stays in button-event mode after copilot exits

### Describe the bug

Using a MinTTY terminal on Windows, user starts Copilot CLI then exits, the terminal is left with button-event mouse tracking mode still enabled.
This means any clicks in the terminal no longer do the usual copy/paste/menu actions but instead cause escape sequences to be input to the terminal.

There are several mouse tracking modes, documented:
https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-Mouse-Tracking
```
┌──────────────────────────┬─────────────┬─────────────┐
│ Mode │ Enable │ Disable │
├──────────────────────────┼─────────────┼─────────────┤
│ Normal click tracking │ \e[?1000h │ \e[?1000l │
├──────────────────────────┼─────────────┼─────────────┤
│ Button-event tracking │ \e[?1002h │ \e[?1002l │
├──────────────────────────┼─────────────┼─────────────┤
│ Any-event tracking │ \e[?1003h │ \e[?1003l │
├──────────────────────────┼─────────────┼─────────────┤
│ SGR extended coordinates │ \e[?1006h │ \e[?1006l │
└──────────────────────────┴─────────────┴─────────────┘
```

The mode which is being left enabled is 1002: Button-event tracking, and 1006: SGR extended coordinates.

The current setting can be queried with `\e[?$p` which gives a response ` \e[?;$y`
Where `` is:

```
┌───────┬───────────────────┐
│ Value │ Meaning │
├───────┼───────────────────┤
│ 1 │ Set (enabled) │
├───────┼───────────────────┤
│ 2 │ Reset (disabled) │
├───────┼───────────────────┤
│ 0 │ Not recognized │
├───────┼───────────────────┤
│ 3 │ Permanently set │
├───────┼───────────────────┤
│ 4 │ Permanently reset │
└───────┴───────────────────┘
```

Example — query normal click tracking (mode 1000):
`bash$ echo -e '\e[?1002$p'`
Terminal replies e.g. `\e[?1002;2$y` → mode 1000 is disabled.

In a fresh terminal, all four modes report `2`: Reset (disabled).
After copilot has run and exited the terminal reports mode 1002 and 1006 are still enabled (`1`). Disabling mode 1002 fixed the terminal behaviour.

### Affected version

GitHub Copilot CLI 1.0.34.

### Steps to reproduce the behavior

1. `echo -e '\e[?1002$p`. Response is `\e[?1002;1$y` - disabled: good.
2. `copilot`
3. `/exit` (or Ctrl-C Ctrl-C)
4. `echo -e '\e[?1002$p`. Response is `\e[?1002;2$y` - enabled: BUG
5. Left-click and drag in the terminal produces a stream of escape sequences: BUG

### Expected behavior

1. `echo -e '\e[?1002$p`. Response is `\e[?1002;1$y` - disabled: good.
2. `copilot`
3. `/exit` (or Ctrl-C Ctrl-C)
4. `echo -e '\e[?1002$p`. Response is `\e[?1002;1$y` - still disabled: good
5. Left-click and drag in the terminal produces a selection. Right-click produces the menu.

### Additional context

Affected terminals:
Cygwin mintty v 3.7.8 (x86_64-pc-cygwin) [Windows 26220]
Git Bash mintty v 3.8.2 (Msys-x86_64) [Windows 26220]

在 Cygwin 或 Git Bash mintty 中查询模式 1002 和 1006、运行 copilot，并使用 /exit 或按两次 Ctrl-C 退出，以重现该问题。跟踪 CLI 的终端设置和清理路径，这些路径在报告中尚未确定。完成标准是退出后两个模式都被重置，并且鼠标选择和上下文菜单正常工作。

由索引模型根据 Issue 内容生成。