- Add loading screen system with stb_image for JPEG loading
- Two loading screen images (orc and dwarf) randomly selected
- Display loading screen while terrain data loads
- Cache WMO inverse matrices to reduce per-frame computation
- Stub WMO liquid rendering (needs coordinate system fix)
- Update spawn point to Stormwind Trade District
- Spawn position changed to (-9080, -100, 100) which is on actual terrain
- The terrain mesh uses WoW coordinates from ADT files directly
- Camera/spawn position must use same coordinate system as terrain
- Cleaned up getHeightAt comments to clarify coordinate system
- Removed debug logging from WMO floor detection