Complete React migration improvements and fixes

- Fix button styling inconsistency for 'did' button using proper CSS reset
- Replace Font Awesome spinners with yellow color (#fff700) for consistency
- Implement holographic card effects for special status cards (yui, first, etc.)
- Add cached user data loading from /json/users.json for faster initial load
- Fix loading states to show spinners instead of "User not found" messages
- Clean up debug console logs for production readiness
- Add proper error handling for API calls
- Update CSS imports to use local files from /pkg/ directory

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

public/pkg/font-awesome/svgs/brands/y-combinator.svg

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