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>

tools/PlaygroundShots.cs

@@ -31,8 +31,8 @@ public partial class PlaygroundShots : Node3D
         floor.AddChild(new CollisionShape3D { Shape = new BoxShape3D { Size = new Vector3(80, 0.1f, 80) }, Position = new Vector3(0, -0.05f, 0) });
         floor.AddChild(new MeshInstance3D { Mesh = new PlaneMesh { Size = new Vector2(80, 80) } });
         AddChild(floor);
-        AddChild(new Playground());
-        AddChild(new Crag());
+        AddChild(GD.Load<PackedScene>("res://scenes/maps/playground.tscn").Instantiate());   // the saved maps
+        AddChild(GD.Load<PackedScene>("res://scenes/maps/crag.tscn").Instantiate());
         _cam = new Camera3D { Current = true };
         AddChild(_cam);
         SetView();