Add M2 global sequence animation, smoke UV scroll, and fix WMO floor detection

- Parse global sequence durations from M2 binary and use them in bone
  interpolation so torches, candles, and other env doodads animate.
- Add UV scroll shader effect for smoke models (HouseSmoke, SmokeStack)
  as a workaround for unimplemented M2 particle emitters.
- Tighten WMO floor probe heights to prevent multi-story buildings from
  returning the wrong floor, fixing player clipping through inn floors
  and camera locking onto the second floor.
- Use player ground level as reference for camera orbit floor collision
  so the camera doesn't fight upper floors in buildings.

include/rendering/m2_renderer.hpp

@@ -56,7 +56,9 @@ struct M2ModelGPU {
     // Skeletal animation data (kept from M2Model for bone computation)
     std::vector<pipeline::M2Bone> bones;
     std::vector<pipeline::M2Sequence> sequences;
+    std::vector<uint32_t> globalSequenceDurations;  // Loop durations for global sequence tracks
     bool hasAnimation = false;  // True if any bone has keyframes
+    bool isSmoke = false;       // True for smoke models (UV scroll animation)
     std::vector<int> idleVariationIndices;  // Sequence indices for idle variations (animId 0)
 
     bool isValid() const { return vao != 0 && indexCount > 0; }