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/world/PearlSpawner.gd

@@ -0,0 +1,116 @@
+extends Node3D
+
+@export var player: NodePath = NodePath("")
+@export var spawn_radius: float = 28.0
+@export var despawn_radius: float = 55.0
+@export var max_pearls: int = 3
+
+const PEARL_SCENE: String = "res://scenes/world/Pearl.tscn"
+const SPAWN_INTERVAL: float = 9.0
+
+var _player_node: CharacterBody3D = null
+var _chunk_manager: Node = null
+var _pearls: Array[Area3D] = []
+var _timer: float = 0.0
+
+
+func _ready() -> void:
+	_resolve_player()
+	_find_chunk_manager()
+
+
+func _resolve_player() -> void:
+	if not player.is_empty():
+		var n: Node = get_node_or_null(player)
+		if n is CharacterBody3D:
+			_player_node = n
+	if _player_node == null:
+		var players := get_tree().get_nodes_in_group("player")
+		if players.size() > 0:
+			_player_node = players[0] as CharacterBody3D
+
+
+func _find_chunk_manager() -> void:
+	var cm: Node = get_node_or_null("/root/Main/World/ChunkManager")
+	if cm != null:
+		_chunk_manager = cm
+
+
+func _physics_process(delta: float) -> void:
+	_timer += delta
+	if _timer < SPAWN_INTERVAL:
+		return
+	_timer = 0.0
+	_resolve_player()
+	_tick()
+
+
+func _tick() -> void:
+	if not is_instance_valid(_player_node):
+		return
+	_cull()
+	if _pearls.size() >= max_pearls:
+		return
+	var pos: Vector3 = _random_spawn_pos()
+	if not _is_valid_spawn(pos):
+		return
+	var packed: PackedScene = load(PEARL_SCENE)
+	if packed == null:
+		return
+	var pearl: Area3D = packed.instantiate() as Area3D
+	if pearl == null:
+		return
+	get_tree().current_scene.add_child(pearl)
+	pearl.global_position = pos
+	if pearl.has_signal("collected"):
+		pearl.collected.connect(_on_pearl_collected)
+	_pearls.append(pearl)
+
+
+func _random_spawn_pos() -> Vector3:
+	var player_pos: Vector3 = _player_node.global_position
+	var angle: float = randf_range(0.0, TAU)
+	var dist: float = randf_range(12.0, spawn_radius)
+	# Pearls float just above the seabed in the shallow-to-mid zone.
+	var depth: float = randf_range(-22.0, 0.0)
+	return Vector3(
+		player_pos.x + cos(angle) * dist,
+		depth,
+		player_pos.z + sin(angle) * dist
+	)
+
+
+func _is_valid_spawn(pos: Vector3) -> bool:
+	if _chunk_manager == null:
+		return true
+	if not _chunk_manager.has_method("get_block"):
+		return true
+	var block_id: int = _chunk_manager.call("get_block", pos)
+	# Avoid spawning inside solid blocks (ids 2..9)
+	if block_id >= 2 and block_id <= 9:
+		return false
+	return true
+
+
+func _cull() -> void:
+	if not is_instance_valid(_player_node):
+		return
+	var ppos: Vector3 = _player_node.global_position
+	var i: int = _pearls.size() - 1
+	while i >= 0:
+		if not is_instance_valid(_pearls[i]):
+			_pearls.remove_at(i)
+		elif _pearls[i].global_position.distance_to(ppos) > despawn_radius:
+			_pearls[i].queue_free()
+			_pearls.remove_at(i)
+		i -= 1
+
+
+func _on_pearl_collected(item_id: int) -> void:
+	var main: Node = get_tree().get_first_node_in_group("main")
+	if main == null or not ("inventory" in main):
+		return
+	main.inventory.add_item(item_id, 1)
+	var am: Node = get_node_or_null("/root/AudioManager")
+	if am != null and am.has_method("play_bubble_sfx") and is_instance_valid(_player_node):
+		am.call("play_bubble_sfx", _player_node.global_position)