fix: wait for playerboard before applying multiplayer sync

scenes/main.gd

@@ -1686,12 +1686,23 @@ func _deferred_set_player_goals(player_id: int, goals: Array):
 			ui_manager.update_playerboard_ui()
 
 
+func _wait_for_playerboard(player_id: int) -> Node:
+	var player = get_node_or_null(str(player_id))
+	var waited := 0.0
+	while (not player or player.playerboard.size() < 25) and waited < 2.0:
+		await get_tree().create_timer(0.1).timeout
+		waited += 0.1
+		player = get_node_or_null(str(player_id))
+	return player if player and player.playerboard.size() >= 25 else null
+
 @rpc("any_peer", "call_local", "reliable")
 func sync_playerboard(player_id: int, new_playerboard: Array):
-	# Find the player and update their playerboard
-	var player = get_node_or_null(str(player_id))
-	if player:
-		player.playerboard = new_playerboard.duplicate()
+	var player = await _wait_for_playerboard(player_id)
+	if not player:
+		push_warning("[sync_playerboard] Dropped update: player %s not ready" % player_id)
+		return
+
+	player.playerboard = new_playerboard.duplicate()
 	
 	# Update UI for local player
 	if player_id == multiplayer.get_unique_id() and GameStateManager.local_player_character:
@@ -1702,9 +1713,16 @@ func sync_playerboard_slot(player_id: int, slot_index: int, item_id: int):
 	"""Patch a single playerboard slot without touching other slots.
 	Used by _execute_grab on grab confirmation to avoid overwriting concurrent
 	in-flight optimistic grab updates on high-latency clients."""
-	var player = get_node_or_null(str(player_id))
-	if player and slot_index >= 0 and slot_index < player.playerboard.size():
+	var player = await _wait_for_playerboard(player_id)
+	if not player:
+		push_warning("[sync_playerboard_slot] Dropped update: player %s not ready" % player_id)
+		return
+
+	if slot_index >= 0 and slot_index < player.playerboard.size():
 		player.playerboard[slot_index] = item_id
+	else:
+		push_warning("[sync_playerboard_slot] Ignored invalid slot %s for player %s" % [slot_index, player_id])
+		return
 	
 	# Update UI for local player only
 	if player_id == multiplayer.get_unique_id() and GameStateManager.local_player_character: