Use CLAUDE.md as single source of truth for AI assistant instructions

## Problem

The project currently maintains multiple AI assistant instruction files with overlapping content:
- `.cursorrules` - for Cursor IDE
- `CLAUDE.md` - for Claude AI
- `.github/copilot-instructions.md` - for GitHub Copilot

Keeping these files synchronized is costly and error-prone.

## Proposed Solution

Use **CLAUDE.md as the single source of truth** and generate other files from it.

### Why CLAUDE.md?
- Already exists in the project
- Markdown format is universal and readable
- Can contain comprehensive instructions that work across platforms
- Clear, descriptive filename

### Implementation Plan

1. **Enhance CLAUDE.md** to include all necessary instructions from other files
2. **Create a sync script** that generates platform-specific files:
- Extract relevant sections for `.cursorrules`
- Generate `.github/copilot-instructions.md` from CLAUDE.md content
- Keep platform-specific quirks documented in CLAUDE.md
3. **Add to development workflow**:
- Run sync script before commits
- Or use git hooks to auto-sync
- Or GitHub Actions for CI/CD

### Benefits
- Single place to update AI instructions
- Consistent guidance across all AI assistants
- Reduced maintenance burden
- Version control tracks changes in one file

### Example Structure for Enhanced CLAUDE.md
```markdown
# ComfyUI Frontend Project Guidelines

## Universal Instructions
[Content that applies to all AI assistants]

## Development Guidelines
[Vue 3, TypeScript, Testing, etc.]

## Platform-Specific Notes
### Cursor
[Any Cursor-specific behavior]

### GitHub Copilot
[Any Copilot-specific behavior]
```

This approach follows the DRY principle and makes maintenance significantly easier.

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-4655-Use-CLAUDE-md-as-single-source-of-truth-for-AI-assistant-instructions-2446d73d36508109ad24f1ee5b8ee93e) by [Unito](https://www.unito.io)