Qualify Godot.Engine: the tools compile test has an Engine namespace

src/RpgBattleService.cs

@@ -58,7 +58,7 @@ namespace Cthangover.Mods.Rpg
 
         private static SceneManager FindSceneManager()
         {
-            var tree = Engine.GetMainLoop() as SceneTree;
+            var tree = Godot.Engine.GetMainLoop() as SceneTree;
             return tree?.Root?.GetNodeOrNull<SceneManager>("SceneManager");
         }
     }

src/World/RpgWorldHost.cs

@@ -78,7 +78,7 @@ namespace Cthangover.Mods.Rpg
             }
 
             RpgState.Instance.Place(mapId, target.X, target.Y, target.Dir);
-            var sceneManager = (Engine.GetMainLoop() as SceneTree)?.Root?.GetNodeOrNull<SceneManager>("SceneManager");
+            var sceneManager = (Godot.Engine.GetMainLoop() as SceneTree)?.Root?.GetNodeOrNull<SceneManager>("SceneManager");
             if (sceneManager == null)
             {
                 GameLogger.Log("RPG", $"teleport to '{mapId}': SceneManager not found", LogLevel.Error);