- Add TextureLoader class using stb_image for PNG/JPG/etc loading
- Integrate TextureLoader with ResourceCache for cached texture loading
- Add SpritePass::setTexture() for binding textures to sprites
- Add "defaultTexture" config option to load texture at startup
- Create assets/textures folder structure
- Add 1f440.png (eyes emoji) test texture
Visual test confirms textured sprites render correctly.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
