Model selection is case sensitive

[PatrickMatthiesen]

Describe the bug

All the models are names with lower case. If a user inputs a upper case name, then the model picking will fail.

Model "GPT-5.4" is unsupported.

  Available models:
    - "claude-sonnet-4.6"
    - "claude-sonnet-4.5"
    - "claude-haiku-4.5"
    - "claude-opus-4.6"
    - "claude-opus-4.5"
    - "claude-sonnet-4"
    - "gemini-3-pro-preview"
    - "gpt-5.4"
    - "gpt-5.3-codex"
    - "gpt-5.2-codex"
    - "gpt-5.2"
    - "gpt-5.1-codex-max"
    - "gpt-5.1-codex"
    - "gpt-5.1"
    - "gpt-5.1-codex-mini"
    - "gpt-5-mini"
    - "gpt-4.1"

  Supported models:
    - "claude-opus-4.6-fast"
    - "claude-opus-4.6-1m"

  For information on Copilot policies and subscription, visit https://github.com/settings/copilot/features

Affected version

GitHub Copilot CLI 1.0.2.

Steps to reproduce the behavior

/models GPT-5.4

Expected behavior

the GPT-5.4 gets selected

Additional context

No response

[ilyazub]

I'd be nice if /model provide autocomplete.