feat: Add initial gridmap mesh library, main game script, and Nakama manager.

scripts/nakama_manager.gd

@@ -102,6 +102,14 @@ func join_game(match_id: String):
 	if not bridge:
 		printerr("Cannot join: Bridge not initialized")
 		return
+
+	# If already connected, leave current match first
+	if bridge.multiplayer_peer.get_connection_status() == MultiplayerPeer.CONNECTION_CONNECTED:
+		print("Already connected to a match. Leaving current match before joining...")
+		bridge.leave()
+		# Wait a bit for cleanup
+		await get_tree().create_timer(0.2).timeout
+		
 	print("Joining match: ", match_id)
 	var result = await bridge.join_match(match_id)
 	if result and result.is_exception():