Replaces heightfield with Cesium Quantized Mesh format (TIN).
Full replacement, not hybrid - TIN is the only terrain format.
Implemented:
- Format: quantizedmeshformat.h, quantizedmeshreader.h
- Triangulator: terraincooker_tin.{h,cpp} using CDT
- Cooker: terraincook now generates TIN by default
- Loader: terraintileloader fully rewritten for TIN
- GPU pool: terraintilepool_tin (VBO/IBO per tile)
- Renderer interface: terrainclipmap.cppm updated
- Shaders: terrainclipmap_tin.{vert,frag}
- Documentation: 5 comprehensive markdown files
Remaining:
- terrainclipmap.cpp render() method (partial, needs completion)
- Build testing and integration
- See TIN_INTEGRATION_GUIDE.md for next steps
Stats: 2700+ lines new code, ~50% vertex reduction expected
