- Create DebugOverlay class using bgfx debug text API
- Display FPS (color-coded: green >55, yellow >30, red <30)
- Show frame time, sprite count, draw calls
- Show GPU/CPU timing and texture stats from bgfx
- Add "debugOverlay" config option to enable at startup
- Smooth FPS display over 250ms intervals
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
