Add property-based mount animation discovery and procedural lean

Mount Animation System:
- Property-based jump animation discovery using sequence metadata
- Chain linkage scoring (nextAnimation/aliasNext) for accurate detection
- Correct loop detection: flags & 0x01 == 0 means looping
- Avoids brake/stop animations via blendTime penalties
- Works on any mount model without hardcoded animation IDs

Mount Physics:
- Physics-based jump height: vz = sqrt(2 * g * h)
- Configurable MOUNT_JUMP_HEIGHT constant (1.0m default)
- Procedural lean into turns for ground mounts
- Smooth roll based on turn rate (±14° max, 6x/sec blend)

Audio Improvements:
- State-machine driven mount sounds (jump, land, rear-up)
- Semantic sound methods (no animation ID dependencies)
- Debug logging for missing sound files

Bug Fixes:
- Fixed mount animation sequencing (JumpStart → JumpLoop → JumpEnd)
- Fixed animation loop flag interpretation (0x20 vs 0x21)
- Rider bone attachment working correctly during all mount actions

include/audio/mount_sound_manager.hpp

@@ -40,6 +40,11 @@ public:
     void setFlying(bool flying);
     void setGrounded(bool grounded);
 
+    // Play semantic mount action sounds (triggered on animation state changes)
+    void playRearUpSound();   // Rear-up flourish (whinny/roar)
+    void playJumpSound();     // Jump start (grunt/snort)
+    void playLandSound();     // Landing (thud/hoof)
+
     bool isMounted() const { return mounted_; }
     void setVolumeScale(float scale) { volumeScale_ = scale; }
     float getVolumeScale() const { return volumeScale_; }
@@ -69,6 +74,7 @@ private:
     bool playingMovementSound_ = false;
     bool playingIdleSound_ = false;
     std::chrono::steady_clock::time_point lastSoundUpdate_;
+    std::chrono::steady_clock::time_point lastActionSoundTime_;  // Cooldown for action sounds
     float soundLoopTimer_ = 0.0f;
 };