Copilot CLI model availability mismatch with web

### Describe the bug

I’m a GitHub Copilot Pro individual user.
In GitHub web Copilot, I can select Claude and Gemini models.
But in Copilot CLI, /model only shows GPT models (no Claude/Gemini).

Environment:
- OS: macOS (Darwin)
- Copilot CLI version: [paste output of /version]
- Account type: Copilot Pro (individual)

What I tried:
- /update
- restart CLI
- /logout then /login
- /model (still no Claude/Gemini)

Expected:
CLI should offer the same model family availability as web (or clearly explain why not).

Please help check whether this is a rollout/entitlement issue on CLI side.

### Affected version

GitHub Copilot CLI 1.0.14

### Steps to reproduce the behavior

_No response_

### Expected behavior

_No response_

### Additional context

_No response_

Start with the CLI's /model and /version entry points and reproduce the model list on Copilot CLI 1.0.14 using the stated Copilot Pro account. Determine whether the mismatch is caused by entitlement or rollout behavior, and consider the issue done when the availability is explained or the CLI exposes the expected model families.

由索引模型根据 Issue 内容生成。