Add shadow toggle (F4) and distance-based WMO group culling

Shadow toggle allows disabling shadow pass for performance testing.
Distance culling skips WMO groups beyond 200 units. Occlusion queries
disabled by default as overhead outweighs benefits in dense scenes.

include/rendering/wmo_renderer.hpp

@@ -428,7 +428,7 @@ private:
     bool frustumCulling = true;
     bool portalCulling = false;  // Disabled by default - needs debugging
     bool distanceCulling = false;  // Disabled - causes ground to disappear
-    bool occlusionCulling = true;  // GPU occlusion queries
+    bool occlusionCulling = false;  // GPU occlusion queries - disabled, adds overhead
     float maxGroupDistance = 500.0f;
     float maxGroupDistanceSq = 250000.0f;  // maxGroupDistance^2
     uint32_t lastDrawCalls = 0;