Wire DBC-driven lighting to terrain shaders:
- Add LightingManager to Renderer
- Initialize lighting manager with AssetManager
- Update lighting each frame with player position
- Feed lighting params to terrain shader uniforms:
* Ambient color
* Diffuse (sun) color and direction
* Fog color, start, end distances
- Fallback to skybox-based fog if lighting unavailable
TODOs for full integration:
- Wire actual map ID from game state
- Wire server game time from login packets
- Add weather/underwater state detection
- Apply lighting to WMO/M2/skybox shaders
Current state: Uses local time + Eastern Kingdoms map (0)
Next: Hook up SMSG_LOGIN_SETTIMESPEED for real game time