Split the object inspector, and sweep out the section banners

objectSection.ts had grown to 559 lines around three separable parts: the
queries, the vector rows and the parent row. Four object commands repeated the
same capture/restore preamble – applyCommands stays out, its five carry extra
undo state whose restore order matters.

58 dashed banner comments are gone. The nine labels in nodes/index.ts stay:
they are the only structure a flat 90-entry array has.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/editor/state.ts

@@ -102,8 +102,6 @@ export class EditorState {
     for (const listener of this.listeners.get(event) ?? []) listener();
   }
 
-  // --- project lifecycle ---------------------------------------------------------------------
-
   loadProject(project: Project, revision: number): void {
     this.edit = null;
     this.mode = 'edit';
@@ -165,8 +163,6 @@ export class EditorState {
     return findScene(this.project, this.project.activeSceneId);
   }
 
-  // --- editing -------------------------------------------------------------------------------
-
   /**
    * Runs a command through the undo stack. Returns false (and sets a notice) when invalid.
    * In play mode the command changes the runtime copy only (see `enterPlay`).
@@ -234,8 +230,6 @@ export class EditorState {
     this.emit('save');
   }
 
-  // --- selection -----------------------------------------------------------------------------
-
   select(selection: Selection): void {
     // Test hooks pass the short form `{ kind: 'object', holderId, objectId }` without `objectIds`.
     // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
@@ -350,8 +344,6 @@ export class EditorState {
     return assetId ? findAsset(this.project, assetId) : undefined;
   }
 
-  // --- status --------------------------------------------------------------------------------
-
   setSaveStatus(status: SaveStatus): void {
     if (this.saveStatus === status) return;
     this.saveStatus = status;