Create comprehensive CasDoc Wiki using Nextra framework

[Copilot]

This PR implements the first comprehensive Wiki for CasDoc using the Nextra framework as requested. The Wiki provides complete user documentation covering all aspects of CasDoc's functionality and usage.

What's Included

📖 Complete Documentation Structure

• Introduction: Overview of CasDoc as a documentation editing tool that enhances traceability through document structure visualization
• Getting Started: Step-by-step guide for new users to create their first documents and understand basic operations
• Core Concepts: Fundamental concepts including document traceability, structure visualization, templates, and content relationships
• User Guide: Comprehensive operational instructions covering document management, content creation, collaboration features, and advanced functionality
• Templates: Detailed template library with examples for User Stories, Test Cases, API Documentation, Procedures, and Checklists
• Best Practices: Guidelines for document organization, content creation, collaboration workflows, and performance optimization

🎯 Key Features Documented

Based on analysis of the CasDoc Web repository, the Wiki covers:

• Document traceability and relationship management
• Template system for structured content creation
• Real-time collaboration capabilities
• Content creation and editing workflows
• Export and integration options
• Security and permissions management
• Search and discovery features

🚀 User-Focused Content

• Written in clear English for end users (not developers)
• Practical examples and step-by-step instructions
• Comprehensive FAQ sections addressing common questions
• Cross-referenced navigation between related topics
• Professional Nextra-based design with responsive sidebar navigation
• Proper table of contents and search functionality

🔧 Technical Implementation

• Built using Nextra framework with nextra-theme-docs
• Proper navigation structure with _meta.js configuration
• MDX format for rich content with tables, code blocks, and interactive elements
• Responsive design with dark/light theme support
• Full build and development environment verification

The Wiki is now fully functional and provides comprehensive guidance for users to effectively utilize CasDoc's documentation editing and traceability features.


Fixes #1.

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