Model System Refactoring and Documentation Translation

[great-majority]

This PR introduces a comprehensive refactoring of the KKStudioSocket model system, transitioning from anonymous objects to strongly-typed request/response models, along with complete translation of project
documentation to English.

Key Changes

🔧 Model System Refactoring

• Replaced anonymous objects with strongly-typed request/response models for better type safety
• Added comprehensive model classes in Models/Requests.cs and Models/Responses.cs
• Refactored all command handlers to utilize new response models:
  • ItemCommandHandler, TreeCommandHandler, ScreenshotCommandHandler
  • CameraCommandHandler, UpdateCommandHandler, HierarchyCommandHandler
  • AddCommandHandler, DeleteCommandHandler, PingCommandHandler

📚 Documentation & Translation

• Translated CLAUDE.md from Japanese to English for international development
• Added comprehensive MODELS.md documenting the new model design and API specifications
• Updated all Jupyter notebooks with latest examples and improvements

🏗️ Technical Improvements

• Enhanced type safety with compile-time type checking
• Improved IntelliSense support for better developer experience
• Unified response format across all API endpoints
• Better error handling with consistent error response models