feat(gameplay): perles collectibles + recette amulette de soin

Area3D Pearl flottant/tournant qui émet une couleur nacrée, spawned
périodiquement près du joueur (PearlSpawner, 3 max, intervalle 9s,
zone haute du seafloor). Collecte automatique au contact, ajout à
l'inventaire (item 105 Perle). Nouvelle recette : 2 perles + 1 corail
rouge → Amulette de soin (item 106, consommable). Spawner désactivé
sur serveur dédié headless.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/Main.gd

@@ -56,6 +56,10 @@ func _ready() -> void:
 		_chat_manager.name = "ChatManager"
 		add_child(_chat_manager)
 
+	# Pearl spawner — skip on dedicated headless (no local player)
+	if not (mode == NetworkManager.Mode.DEDICATED and DisplayServer.get_name() == "headless"):
+		_spawn_pearl_system()
+
 	# Audio
 	AudioManager.play_ambient_loop("underwater_ambient")
 	AudioManager.play_music("underwater_theme")
@@ -158,6 +162,18 @@ func _spawn_mobs() -> void:
 		mob_spawner.player = mob_spawner.get_path_to(_my_dolphin)
 
 
+func _spawn_pearl_system() -> void:
+	var spawner_script: Script = load("res://scripts/world/PearlSpawner.gd")
+	if spawner_script == null:
+		return
+	var spawner := Node3D.new()
+	spawner.name = "PearlSpawner"
+	spawner.set_script(spawner_script)
+	add_child(spawner)
+	if is_instance_valid(_my_dolphin):
+		spawner.player = spawner.get_path_to(_my_dolphin)
+
+
 func _connect_dolphin_signals(dolphin: CharacterBody3D) -> void:
 	if dolphin.has_signal("block_break_requested"):
 		dolphin.block_break_requested.connect(_on_block_break)