New Features:
- Procedural pixelated textures (16x16) for each tile
- Unique patterns per tile using Perlin noise
- Retro pixel-art style with GL_NEAREST filtering
- Random heightmap seed on regeneration
- Random texture seed on regeneration
Technical:
- OpenGL texture generation with glTexImage2D
- 3-layer Perlin noise (detail, pattern, spots)
- Texture caching per tile
- GPU texture cleanup on regeneration
Visual:
- RollerCoaster Tycoon-style grass patches
- Dark spots and color variations
- Biome-contextual textures
- Uniform brown side faces with shading