Clean up repo for public release

Removed:
- Old planning docs (DEPLOYMENT.md, IMPLEMENTATION.md, etc.)
- Dev notes (thursday-aims-progress-problems.md)
- Old backup files (main-simple.ts, main-working.ts)
- Test file (test.html)
- Unused image (chiptune_blog_piece_1000x.webp)
- docs/ folder with old audit/plan docs

Updated:
- Renamed claude.md to CLAUDE.md
- Added .claude/ to gitignore

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitignore

@@ -34,6 +34,7 @@ logs/
 .cache/
 .tmp/
 .vercel
+.claude/
 
 # Backend runtime cache (downloaded MIDI files)
 server/cache/