Close [AI-116](https://linear.app/affine-design/issue/AI-116)
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Added support for specifying alternative AI models in chat prompts, enabling users to select from multiple available models.
- Expanded AI model options with new additions: 'gpt-4.1', 'o3', and 'claude-3-5-sonnet-20241022'.
- **Enhancements**
- Users can now optionally choose a specific AI model during chat interactions.
- Prompts and chat sessions reflect and support selection of alternative models where applicable.
- **Bug Fixes**
- Improved handling of prompt configuration defaults for better reliability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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