Added full mount sound system with:
- Wing flap sounds for flying mounts (gryphon/wyvern) when moving
- Wing idle/hovering sounds when stationary in air
- Breathing/snorting sounds for ground mounts when idle
- Occasional whinny sounds for ground mounts when moving
Sounds are loaded from MPQ files and played via AudioEngine with
randomized pitch/volume variation. Mount sound manager tracks mount
type, movement state, and flying state to play appropriate ambient
sounds at natural intervals.
Updated setMounted() to accept creature display ID and notify the
mount sound manager, which uses display ID ranges to detect mount
type (flying vs ground).
Implement framework for playing mount sounds (flapping, galloping) based on mount type and movement state. Actual sound playback to be implemented next.
