Root nodes join through ModRoot.AddDeferred, so a reload that unloads the mod first never hands Godot a freed node

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

test_suites/edit/manifest.json

@@ -1,6 +1,6 @@
 {
   "name": "Item Editor Test",
-  "description": "GUI test of the item editor in rpg_demo: opens rpg_demo_game's items, shows a demo item's localized name, adds an item with the New button, types its name, price and a type into the form, copies it and undoes the copy with Ctrl+Z, saves; the game must know the item and its name at once and the other item files stay unchanged. The new file and the locale edits are removed again. Activated by --itest=items_editor_edit with --game=rpg_demo --new.",
+  "description": "GUI test of the item editor in rpg_plus: opens rpg_demo_game's items, shows a demo item's localized name, adds an item with the New button, types its name, price and a type into the form, copies it and undoes the copy with Ctrl+Z, saves; the game must know the item and its name at once and the other item files stay unchanged. The new file and the locale edits are removed again. Activated by --itest=items_editor_edit with --game=rpg_plus --new (the prologue is clicked through first).",
   "sources": [
     "src/*.cs"
   ],

test_suites/edit/src/ItemEditorTestInitializer.cs

@@ -27,7 +27,7 @@ namespace Cthangover.Tools.ItemsEditor.Tests
                 .Select(a => a.Substring("--shots=".Length))
                 .FirstOrDefault();
             GameLogger.Log("TEST", $"ItemEditorTestInitializer: activating items_editor_edit, shots={shots ?? "off"}");
-            (Godot.Engine.GetMainLoop() as SceneTree)?.Root?.CallDeferred("add_child", new ItemEditorTestDriver(shots));
+            ModRoot.AddDeferred(new ItemEditorTestDriver(shots));
         }
     }
 }