Add ambient sound system and eliminate log spam

- Implement AmbientSoundManager with tavern/outdoor ambience
- Fix audio buffer limit (5s → 60s) for long ambient loops
- Set log level to INFO to eliminate DEBUG spam (130MB → 3.2MB logs)
- Remove excessive terrain/model/network logging
- Fix ambient sound timer sharing and pitch parameter bugs

include/core/logger.hpp

@@ -62,7 +62,7 @@ private:
         return oss.str();
     }
 
-    LogLevel minLevel = LogLevel::DEBUG;
+    LogLevel minLevel = LogLevel::INFO;  // Changed from DEBUG to reduce log spam
     std::mutex mutex;
     std::ofstream fileStream;
     bool fileReady = false;