API-Based Model Validation

What: The /model command now validates custom model names by making a test API request before accepting them.

How to use:

# Try setting a custom model - it will be validated first
/model claude-opus-4-20250514

# If the model doesn't exist, you'll get an error immediately:
# "Model 'claude-opus-4-20250514' not found"

Details:

• Validation occurs automatically when setting custom models
• Built-in models (sonnet, haiku, opus) bypass validation for faster response
• Validated models are cached to avoid repeated API calls
• Provides specific error messages for model-not-found vs other API errors
• Evidence: HDB() at line 425289 in v1.0.111.js