Merge origin/main which includes:
- New file sharing system (shares module)
- Large markdown viewer improvements
- Preview page refactoring
- FloatingToc component
Preserved from local:
- LLM model configuration support (llm_model_configs)
This merge integrates remote improvements while keeping the local
model configuration functionality for the next phase.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
mula.liu