Maps are editor-built scenes: [Tool] Playground/Crag, headless rebuild for agents

scenes/maps/playground.tscn and crag.tscn are generated by the map scripts' Rebuild (inspector
button, or godot-mono --headless --path . tools/rebuild_maps.tscn) and loaded as saved by the game,
so hand edits stick. The crag route is saved as Marker3D nodes and crag_spike checks the saved
scene. Layout verified identical to the code-built one (tools/map_dump.tscn).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/RagdollSpike.cs

@@ -1128,7 +1128,8 @@ public partial class RagdollSpike : Node3D
     private void SetupPlayground()
     {
         Rest();
-        _playground = new Playground { Position = new Vector3(0f, 0f, 40f) };   // far from the player
+        _playground = GD.Load<PackedScene>("res://scenes/maps/playground.tscn").Instantiate<Playground>();   // the saved scene
+        _playground.Position = new Vector3(0f, 0f, 40f);   // far from the player
         _stage.AddChild(_playground);
     }