feat: optimize AI rules with unified .rules.md (#401)

* feat: optimize AI rules with unified .rules.md and entry points

- Create .rules.md as the central AI coding rules file
- Add .copilot-rules.md as GitHub Copilot entry point
- Add CLAUDE.md as Claude AI entry point
- Incorporate principles from rustfs.com project
- Add three critical rules:
  1. Use English for all code comments and documentation
  2. Clean up temporary scripts after use
  3. Only make confident modifications

* Update CLAUDE.md

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>

.copilot-rules.md

@@ -0,0 +1,58 @@
+# GitHub Copilot Rules for RustFS Project
+
+## Core Rules Reference
+
+This project follows the comprehensive AI coding rules defined in `.rules.md`. Please refer to that file for the complete set of development guidelines, coding standards, and best practices.
+
+## Copilot-Specific Configuration
+
+When using GitHub Copilot for this project, ensure you:
+
+1. **Review the unified rules**: Always check `.rules.md` for the latest project guidelines
+2. **Follow branch protection**: Never attempt to commit directly to main/master branch
+3. **Use English**: All code comments, documentation, and variable names must be in English
+4. **Clean code practices**: Only make modifications you're confident about
+5. **Test thoroughly**: Ensure all changes pass formatting, linting, and testing requirements
+
+## Quick Reference
+
+### Critical Rules
+- 🚫 **NEVER commit directly to main/master branch**
+- ✅ **ALWAYS work on feature branches**
+- 📝 **ALWAYS use English for code and documentation**
+- 🧹 **ALWAYS clean up temporary files after use**
+- 🎯 **ONLY make confident, necessary modifications**
+
+### Pre-commit Checklist
+```bash
+# Before committing, always run:
+cargo fmt --all
+cargo clippy --all-targets --all-features -- -D warnings
+cargo check --all-targets
+cargo test
+```
+
+### Branch Workflow
+```bash
+git checkout main
+git pull origin main
+git checkout -b feat/your-feature-name
+# Make your changes
+git add .
+git commit -m "feat: your feature description"
+git push origin feat/your-feature-name
+gh pr create
+```
+
+## Important Notes
+
+- This file serves as an entry point for GitHub Copilot
+- All detailed rules and guidelines are maintained in `.rules.md`
+- Updates to coding standards should be made in `.rules.md` to ensure consistency across all AI tools
+- When in doubt, always refer to `.rules.md` for authoritative guidance
+
+## See Also
+
+- [.rules.md](./.rules.md) - Complete AI coding rules and guidelines
+- [CONTRIBUTING.md](./CONTRIBUTING.md) - Contribution guidelines
+- [README.md](./README.md) - Project overview and setup instructions