测试：完成BGM提示词优化收口并切换助手模型

增加 TypeScript/Rust 共用 canonicalization fixture
补齐 BGM 跨层等值、SFX 和后端边界测试
将 BGM 补全与简化请求模型改为 gpt-5.6-luna，保留画布 Agent gpt-5.4-mini
同步权威设计、项目记忆和 T6 发布门禁记录
验证本地定向测试与真实 VectorEngine 补全/简化请求

src/services/image-editor/editorProjectClient.test.ts

@@ -1,5 +1,6 @@
 import { afterEach, describe, expect, it, vi } from 'vitest';
 
+import backgroundMusicPromptCanonicalizationCases from '../../../packages/shared/test-fixtures/background-music-prompt-canonicalization.json';
 import {
   completeEditorBackgroundMusicPrompt,
   createEditorAsset,
@@ -1582,13 +1583,21 @@ describe('editorProjectClient', () => {
   });
 
   it('generates editor background music through the backend BFF', async () => {
+    const representativeComplexPromptCase =
+      backgroundMusicPromptCanonicalizationCases.find(
+        ({ name }) => name === 'representative-complex',
+      );
+    if (!representativeComplexPromptCase) {
+      throw new Error('missing representative-complex prompt fixture');
+    }
+    const canonicalPrompt = representativeComplexPromptCase.prompt;
     requestJsonMock.mockResolvedValueOnce({
       audioSrc: '/generated-character-drafts/editor-audios/bgm.mp3',
       width: 420,
       height: 120,
       sourceType: 'generated',
-      prompt: '森林冒险背景音乐',
-      actualPrompt: '森林冒险背景音乐',
+      prompt: canonicalPrompt,
+      actualPrompt: canonicalPrompt,
       model: 'chirp-v4',
       provider: 'VectorEngine',
       taskId: 'music-task-1',
@@ -1596,7 +1605,7 @@ describe('editorProjectClient', () => {
     });
 
     const result = await generateEditorBackgroundMusic({
-      gptDescriptionPrompt: '森林冒险背景音乐',
+      gptDescriptionPrompt: canonicalPrompt,
       makeInstrumental: true,
       assetFolderId: 'project',
       assetLabel: '游戏背景音乐 1',
@@ -1609,7 +1618,7 @@ describe('editorProjectClient', () => {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({
-          gptDescriptionPrompt: '森林冒险背景音乐',
+          gptDescriptionPrompt: canonicalPrompt,
           makeInstrumental: true,
           assetFolderId: 'project',
           assetLabel: '游戏背景音乐 1',