feat(extract): build containment tree and traverse all containers

Add buildTree to mirror how TTS nests objects, with a display label
(Nickname or class Name). Generalize traverseMod to descend into any
object with ContainedObjects, not just bags, and add Nickname to
TTSObject.

packages/extract/src/objects.test.ts

@@ -1,6 +1,11 @@
 import { describe, expect, it } from 'vitest';
 import type { TTSMod, TTSObject } from '@tts/shared';
-import { filterObjects, findObject, flattenObjects } from './objects.js';
+import {
+  buildTree,
+  filterObjects,
+  findObject,
+  flattenObjects,
+} from './objects.js';
 
 function card(guid: string, name = 'Card'): TTSObject {
   return { Name: name, GUID: guid, Description: '' };
@@ -21,14 +26,15 @@ const mod: TTSMod = {
 };
 
 describe('flattenObjects', () => {
-  it('returns every object including those inside bags', () => {
+  it('returns every object including containers and those inside them', () => {
     const guids = flattenObjects(mod).map((o) => o.GUID);
-    expect(guids).toEqual(['a', 'c', 'd', 'e']);
+    expect(guids).toEqual(['a', 'b', 'c', 'd', 'e']);
   });
 
   it('sets Parent links before returning', () => {
-    const [a, c] = flattenObjects(mod);
+    const [a, b, c] = flattenObjects(mod);
     expect(a!.Parent).toBeUndefined();
+    expect(b!.Parent).toBeUndefined();
     expect(c!.Parent!.GUID).toBe('b');
   });
 });
@@ -48,4 +54,26 @@ describe('findObject', () => {
   it('returns undefined for a missing GUID', () => {
     expect(findObject(mod, 'zzz')).toBeUndefined();
   });
+});
+
+describe('buildTree', () => {
+  it('mirrors the containment hierarchy', () => {
+    const tree = buildTree(mod);
+    expect(tree.map((n) => n.object.GUID)).toEqual(['a', 'b', 'e']);
+    expect(tree[1]!.children.map((n) => n.object.GUID)).toEqual(['c', 'd']);
+  });
+
+  it('uses Nickname as the label when present', () => {
+    const named = {
+      ...card('n', 'Card'),
+      Nickname: 'Ace of Spades',
+    };
+    const tree = buildTree({ ...mod, ObjectStates: [named] });
+    expect(tree[0]!.label).toBe('Ace of Spades');
+  });
+
+  it('falls back to the class Name as the label', () => {
+    const tree = buildTree(mod);
+    expect(tree[0]!.label).toBe('Deck');
+  });
 });