Support for Gemini & Anthropic models and improvements

New Features
New AI Providers: Support for Gemini and Anthropic models
Custom Thinking Blocks: You can now use special <thinking> blocks in Markdown to format thoughts or ideas more clearly.
Improvements
Better Chat Experience: Behind-the-scenes upgrades to make conversations smoother and more flexible.
UI Enhancements: Cleaner layouts, improved styling, and more intuitive controls across chat and document areas.
Smarter File Handling: The file manager now offers better tools for organizing and working with documents.
Language Model Editor Updates: More options and clearer controls for managing your AI models.