Refactor round 2: fold duplicated command and inspector code

- applyCommands sit on ObjectEditCommand with a revert hook instead of
  five copies of the same preamble and undo
- actionIf replaces six identical Reset/Apply menu blocks, addNameField
  the three name rows, assetLink the two asset links
- requireStructuralObject replaces ten two-line preambles and drops the
  duplicate holder lookup
- __gm.objectsOf had no caller; the SMB remnant in e2e.sh is gone

Proven: check.sh 797 tests, full e2e 633 checks, smokes 24/19/20 against
the same bundle.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/editor/debugHook.ts

@@ -168,7 +168,6 @@ export function installDebugHook(app: Application, state: EditorState, editor: E
   };
   (window as unknown as { __gm: unknown }).__gm = {
     state,
-    objectsOf,
     sceneObjects: () => (state.activeScene ? objectsOf(state.activeScene.id) : []),
     locate,
     locateAll,