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.

src/pipeline/m2_loader.cpp

@@ -422,6 +422,13 @@ M2Model M2Loader::load(const std::vector<uint8_t>& m2Data) {
         core::Logger::getInstance().debug("  Animation sequences: ", model.sequences.size());
     }
 
+    // Read global sequence durations (used by environmental animations: smoke, fire, etc.)
+    if (header.nGlobalSequences > 0 && header.ofsGlobalSequences > 0) {
+        model.globalSequenceDurations = readArray<uint32_t>(m2Data,
+            header.ofsGlobalSequences, header.nGlobalSequences);
+        core::Logger::getInstance().debug("  Global sequences: ", model.globalSequenceDurations.size());
+    }
+
     // Read bones with full animation track data
     if (header.nBones > 0 && header.ofsBones > 0) {
         // Verify we have enough data for the full bone structures