Add bell tolls for major cities marking time

Implemented periodic bell chimes that add atmosphere to major cities:

Bell types by faction:
- Alliance bell: Stormwind, Ironforge
- Night Elf bell: Darnassus
- Horde bell: Orgrimmar, Undercity
- Tribal bell: Thunder Bluff

Technical details:
- Loads 4 bell toll sound files from Sound\Doodad
- Plays every 120-180 seconds (2-3 minutes) with random variation
- First bell toll 60-90 seconds after entering city
- Volume at 0.5 for noticeable but not overpowering effect
- Only plays when currentCity_ is set (not in wilderness)
- Each city uses faction-appropriate bell sound
- Separate timer (bellTollTime_) from regular city ambience
- State logging for debugging bell events

include/audio/ambient_sound_manager.hpp

@@ -152,6 +152,12 @@ private:
     std::vector<AmbientSample> thunderbluffDaySounds_;
     std::vector<AmbientSample> thunderbluffNightSounds_;
 
+    // City bell sounds
+    std::vector<AmbientSample> bellAllianceSounds_;
+    std::vector<AmbientSample> bellHordeSounds_;
+    std::vector<AmbientSample> bellNightElfSounds_;
+    std::vector<AmbientSample> bellTribalSounds_;
+
     // Active emitters
     std::vector<AmbientEmitter> emitters_;
     uint64_t nextEmitterId_ = 1;
@@ -167,6 +173,7 @@ private:
     float oceanLoopTime_ = 0.0f;
     float zoneLoopTime_ = 0.0f;
     float cityLoopTime_ = 0.0f;
+    float bellTollTime_ = 0.0f;
     bool wasIndoor_ = false;
     bool wasBlacksmith_ = false;
     bool wasSwimming_ = false;
@@ -191,6 +198,7 @@ private:
     void updateWaterAmbience(float deltaTime, bool isSwimming);
     void updateZoneAmbience(float deltaTime, bool isIndoor);
     void updateCityAmbience(float deltaTime);
+    void updateBellTolls(float deltaTime);
     bool loadSound(const std::string& path, AmbientSample& sample, pipeline::AssetManager* assets);
 
     // Time of day helpers