/model picker should respect ANTHROPIC_DEFAULT_*_MODEL_NAME env vars

Describe the bug

The /model command's "Default" row shows the model tier name (e.g., "Opus 4.7 (1M context)") instead of the value from ANTHROPIC_DEFAULT_OPUS_MODEL_NAME environment variable.

When using a proxy that maps model IDs to different providers/models, the _MODEL_NAME env vars are meant to control the display name. This works in the status bar, but the /model picker ignores it.

To reproduce

In ~/.claude/settings.json:

{
  "env": {
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "claude-opus-4-7[1M]",
    "ANTHROPIC_DEFAULT_OPUS_MODEL_NAME": "mimo-v2.5-pro"
  }
}

Run /model and observe the "Default" row shows "currently Opus 4.7 (1M context)" instead of "currently mimo-v2.5-pro".

Expected behavior

The /model picker's "Default" row should display the value from ANTHROPIC_DEFAULT_OPUS_MODEL_NAME (e.g., "mimo-v2.5-pro") when set, consistent with the status bar behavior.

Environment

• Claude Code version: 2.1.149
• OS: Windows 11 Pro 10.0.26200
• Installation: standalone executable