Claude (Sonnet 4.6) on AUTOPILOT seems wrongly integrated, doesnt terminate, stop or do anything, keeps infinate internal conversation

### Describe the bug

Since this was working a month ago something fundamentally seem to have been broken.

When select the mentioned model then nothing results from it, it just keeps infinitely looking on internal conversation, this wasnt the case when i used copilot last month, so something must have been broken in the Anthropic model integration.

### Affected version

GitHub Copilot CLI 1.0.40

### Steps to reproduce the behavior

1. Select Sonnet 4.6 (maybe also other, i only tested this)
2. set on autopilot maybe
3. ask it to do literally anything
4. wont reach a result

### Expected behavior

just reach a conclusion, result, fix whatever, instead of infinitely circling in internal conversation and draining tokens

### Additional context

$PSVersionTable

Name Value
---- -----
PSVersion 7.6.1
PSEdition Core
GitCommitId 7.6.1
OS Microsoft Windows 10.0.26200
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion 2.4
SerializationVersion 1.1.0.1
WSManStackVersion 3.0

まず、Windows 10 上の PowerShell 7.6.1 で autopilot に Claude Sonnet 4.6 を選択した状態で、GitHub Copilot CLI 1.0.40 の問題を再現します。autopilot を無効にした場合や別のモデルを使用した場合の動作と比較し、CLI が無限ループしてトークンを消費し続けるのではなく、結論に到達するか停止すれば、問題は解決したと判断します。

索引モデルが issue の本文から書いたものです。