- Add AudioManager autoload with music and sfx players
- Add ambiance tracks for entrepot, atelier and cour zones
- Add SFX for footstep, item_pickup, interact, door_unlock, repair_success, vrac_talking, iris_talking
- Add crossfade transition between ambiance zones
- Add loop via finished signal on music_player
- Set ambiance volume to -12dB to balance with SFX
- Set PROCESS_MODE_ALWAYS to prevent audio cut during dialogues
- Add stop_ambiance() call on main_menu to reset music after credits