Initial commit: OpenRA game engine

Fork from OpenRA/OpenRA with one-click launch script (start-ra.cmd)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

OpenRA.Mods.Common/Lint/CheckMapTiles.cs

@@ -0,0 +1,24 @@
+#region Copyright & License Information
+/*
+ * Copyright (c) The OpenRA Developers and Contributors
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+
+namespace OpenRA.Mods.Common.Lint
+{
+	public class CheckMapTiles : ILintMapPass
+	{
+		public void Run(Action<string> emitError, Action<string> emitWarning, ModData modData, Map map)
+		{
+			foreach (var kv in map.ReplacedInvalidTerrainTiles)
+				emitError($"Cell `{kv.Key}` references invalid terrain tile `{kv.Value}`.");
+		}
+	}
+}