fix(candy-survival): connect Ghost charges to SpecialTilesManager powerup inventory, spawn Ghost tiles in arena, and support powerup button activations

scripts/managers/special_tiles_manager.gd

@@ -153,6 +153,17 @@ func add_powerup_from_item(item_id: int):
 	var effect = get_effect_from_item(item_id)
 	if effect == -1: return
 
+	if LobbyManager.game_mode == "Candy Survival":
+		if effect == SpecialEffect.INVISIBLE_MODE:
+			var gm = player.get_node_or_null("/root/Main/CandySurvivalManager")
+			if gm and gm.active:
+				var pid = player.get("peer_id") if "peer_id" in player else player.name.to_int()
+				if multiplayer.is_server():
+					gm.add_ghost_charge(pid)
+				else:
+					gm.rpc_id(1, "add_ghost_charge", pid)
+			return
+
 	# VFX: show pickup burst on all peers (mirrors skill VFX pattern)
 	if player.is_multiplayer_authority() and player.has_method("can_rpc") and player.can_rpc():
 		player.rpc("play_skill_vfx", "take_powerup")
@@ -230,6 +241,17 @@ func activate_effect(effect: int, target_player: Node3D = null):
 		NotificationManager.send_message(player, "Skill in Cooldown! (%.1fs)" % global_cooldown_timer, NotificationManager.MessageType.WARNING)
 		return
 		
+	if LobbyManager.game_mode == "Candy Survival":
+		if effect == SpecialEffect.INVISIBLE_MODE:
+			var gm = player.get_node_or_null("/root/Main/CandySurvivalManager")
+			if gm and gm.active:
+				var pid = player.get("peer_id") if "peer_id" in player else player.name.to_int()
+				if multiplayer.is_server():
+					gm.try_activate_ghost(pid)
+				else:
+					gm.rpc_id(1, "try_activate_ghost", pid)
+			return
+		
 	# Check Attack Mode Restriction
 	if player.get("is_attack_mode") and effect == SpecialEffect.INVISIBLE_MODE:
 		NotificationManager.send_message(player, "Cannot enter Ghost mode while in Attack Mode!", NotificationManager.MessageType.WARNING)