Fix mount sounds, grey WMO meshes, taxi landing, tree animations, and classic dismount

- Per-family mount sounds (kodo, tallstrider, mechanostrider, etc.) detected from M2 model path
- Skip WMO groups with SHOW_SKYBOX flag or all-untextured batches (grey mesh in Orgrimmar)
- Freeze physics during taxi landing until terrain loads to prevent falling through void
- Disable bone animations on tropical vegetation (palm, bamboo, banana, etc.) to fix wiggling
- Snap player to final taxi waypoint on flight completion
- Extract mount aura spell ID from classic UNIT_FIELD_AURAS for CMSG_CANCEL_AURA dismount
- Increase /unstuck forward nudge to 5 units

include/game/update_field_table.hpp

@@ -29,6 +29,7 @@ enum class UF : uint16_t {
     UNIT_FIELD_FLAGS_2,
     UNIT_FIELD_DISPLAYID,
     UNIT_FIELD_MOUNTDISPLAYID,
+    UNIT_FIELD_AURAS,           // Start of aura spell ID array (48 consecutive uint32 slots, classic/vanilla only)
     UNIT_NPC_FLAGS,
     UNIT_DYNAMIC_FLAGS,
     UNIT_END,