Enhanced CLI with improved configuration, new commands, and comprehensive documentation

[lolsZz]

This PR enhances the DeepSeek CLI with the following improvements:

Enhancements

• Added support for multiple configuration sources (environment variables, .env file, .deepseekrc file)
• Added new 'analyze' command for code review and analysis
• Added new 'models' command to list available DeepSeek models
• Added support for both available DeepSeek models: deepseek-chat and deepseek-reasoner
• Added model validation to ensure only valid models are used
• Added additional command-line options (temperature, max-tokens)
• Enhanced error handling for API calls
• Improved response formatting for better readability

Advanced Features

• Added streaming responses for real-time output
• Added new 'reason' command for complex problem solving with the deepseek-reasoner model
• Added Chain of Thought (CoT) reasoning display with the --show-reasoning flag
• Added support for streaming API responses
• Added new 'tokens' command for counting tokens and estimating API costs
• Added contextual token usage information after each API call
• Added session token tracking in interactive mode
• Added 'stats' command in interactive mode to display session statistics
• Enhanced error handling for streaming responses

Accessibility Improvements

• Added human-friendly command aliases for improved accessibility
• Added 'ask' alias for the 'chat' command
• Added 'solve' alias for the 'reason' command
• Added 'review' alias for the 'analyze' command
• Added 'count' alias for the 'tokens' command
• Added 'list' alias for the 'models' command
• Added task-specific commands: 'explain', 'fix', 'improve', and 'cost'
• Enhanced help text with better organization and examples

User Experience Improvements

• Added multi-turn conversation support in interactive mode
• Added conversation history tracking for context-aware responses
• Added enhanced interactive mode with slash commands (/help, /clear, /stats, /model, /exit)
• Added improved welcome message with command information
• Added better user guidance throughout the application

Documentation

• Updated README.md with new features and improved instructions
• Added CHANGELOG.md to track version changes
• Added CONTRIBUTING.md with guidelines for contributors
• Added HELP.md with comprehensive documentation
• Updated package.json with new version and improved metadata
• Added documentation structure section explaining api-docs and deepseek-docs folders
• Added comprehensive model comparison and pricing information
• Added detailed explanations of model capabilities and limitations
• Included DeepSeek V3 tokenizer for reference

Bug Fixes

• Fixed environment variable loading issue
• Improved error handling for configuration loading
• Fixed maxTokens parsing issue
• Fixed multi-turn conversation support in interactive mode

These improvements make the CLI more robust, user-friendly, and feature-rich.