feat(core/frontend): wire settings/avatar/image-gen + real data render (library/product-detail/pipeline)

App.tsx: thread saveProfile/changePassword/uploadAvatar/generateImages handlers + assets prop to pages.
- settings.tsx: profile save / password modal / avatar upload wired; notification/theme prefs -> localStorage
- library.tsx + product-detail: asset thumbnails + grids render real TOS preview_url
- ai-tools ImageWorkbenchPage: 生成图片 wired to /api/ai/generate-image, renders returned assets
- pipeline.tsx stage2-5: base_assets/storyboard/video_segments(adopted_asset)/timeline(clips/subtitles/bgm)
  rendered from real project data; graceful empty states
- types.ts: +VideoSegment.adopted_asset, +Timeline.subtitle_tracks/bgm_tracks
verified: tsc --noEmit clean; screenshots confirm pipeline stages 2-5 + product-detail render real data+images
(demo asset object_keys re-pointed to image objects so thumbnails resolve)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

core/frontend/src/library-page.css

@@ -6,6 +6,8 @@
   .asset-card:hover { background: var(--background-lighter); border-color: var(--black-alpha-48); }
   .asset-thumb { aspect-ratio: 1; }
   .asset-card.video .asset-thumb { aspect-ratio: 9/16; max-height: 280px; }
+  /* 有 preview_url 显真图:铺满缩略容器、cover 裁切、继承 8px 圆角(由 .placeholder overflow:hidden 裁切) */
+  .asset-thumb img { width: 100%; height: 100%; object-fit: cover; display: block; border-radius: inherit; }
   .asset-body { padding: 12px 14px; }
   .asset-name { font-size: 13px; font-weight: 600; color: var(--accent-black); }
   .asset-meta { font-size: 11px; color: var(--black-alpha-48); margin-top: 3px; font-family: var(--font-mono); letter-spacing: .02em; }