docs: add CLAUDE.md for Claude Code guidance

Add comprehensive documentation for Claude Code instances working with this repository, including:
- Development commands and workflow
- Repository architecture and content structure
- mdBook-specific guidelines for Vietnamese Rust book
- CI/CD pipeline information

Author: duyet

CLAUDE.md

@@ -0,0 +1,105 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Repository Overview
+
+This is a Vietnamese language Rust book built with mdBook - a comprehensive resource for learning Rust programming in Vietnamese. The book covers fundamental concepts through advanced topics and practical examples.
+
+## Development Commands
+
+### Local Development
+```bash
+# Start development server (auto-installs dependencies)
+./dev.sh
+
+# Start with custom port
+./dev.sh 3001
+
+# Manual setup and serve
+cargo install mdbook mdbook-linkcheck
+mdbook serve --open --port 3000
+```
+
+### Building the Book
+```bash
+# Build the book for production
+mdbook build
+
+# Check links
+mdbook-linkcheck
+```
+
+### Testing
+```bash
+# Test Rust code examples in the book
+mdbook test
+
+# Run tests for specific chapter
+mdbook test src/basic/
+```
+
+## Architecture & Structure
+
+### Content Organization
+- **`src/`** - All book content in Markdown format
+  - **`SUMMARY.md`** - Table of contents defining book structure
+  - **`basic/`** - Fundamental Rust concepts (variables, ownership, structs, traits, enums)
+  - **`advanced/`** - Advanced topics (smart pointers, async programming)
+  - **`crates/`** - Popular crate documentation and examples
+  - **`design-pattern/`** - Rust design patterns and idioms
+  - **`data-engineering/`** - Data processing and analysis with Rust
+  - **`getting-started/`** - Installation and first project guides
+
+### Key Configuration Files
+- **`book.toml`** - mdBook configuration with Vietnamese language settings
+- **`dev.sh`** - Development script with auto-dependency installation
+- **`src/lib.rs`** - Minimal Rust file for GitHub language detection
+
+### Content Structure Patterns
+1. **Hierarchical Topics** - Each major concept has its own directory with README.md
+2. **Progressive Complexity** - Basic → Advanced → Specialized topics
+3. **Practical Examples** - Rust code files (`.rs`) embedded in chapters
+4. **Vietnamese Language** - All content in Vietnamese with technical terms explained
+
+### Build System
+- **mdBook** - Static site generator for technical documentation
+- **GitHub Actions** - Automated deployment to GitHub Pages
+- **Link Checking** - Validates all links in the book content
+
+## Development Workflow
+
+### Adding New Content
+1. Create/update Markdown files in `src/` directory
+2. Update `src/SUMMARY.md` if adding new chapters
+3. Include practical Rust code examples where appropriate
+4. Test locally with `./dev.sh` before committing
+
+### Content Guidelines
+- Write in Vietnamese with clear explanations
+- Include runnable Rust code examples
+- Use consistent formatting and terminology
+- Link to related concepts within the book
+
+### CI/CD Pipeline
+- **PR Builds** - Every PR builds the book and checks links
+- **Deployment** - Main branch automatically deploys to GitHub Pages
+- **Sitemap Generation** - Automatically generates sitemap for SEO
+- **Link Validation** - mdbook-linkcheck validates all external links
+
+## Book-Specific Considerations
+
+### Language and Localization
+- Primary language: Vietnamese (`vi`)
+- Technical terms include both Vietnamese and English
+- Code examples use English variable names with Vietnamese comments
+
+### Content Validation
+- All Rust code examples should compile and run
+- Links should be validated with mdbook-linkcheck
+- Vietnamese grammar and terminology should be consistent
+
+### Performance
+- Static site generation allows fast loading
+- GitHub Pages provides reliable hosting
+- Responsive design for mobile and desktop reading