feat(core/frontend): pipeline stage editor (burn-in controls) + double-submit guard & button greying

Pipeline (脚本→资产→故事板→视频→拼接):
- Stage1 render real script shots + wire 确认脚本→adopt (advance stage)
- Stage2 add person/scene AI-生成 buttons + clickable category tabs
- Stage4 auto-poll videos to completion + per-segment upload + real frame thumbnails + download
- Stage5 real timeline editor: clips undo/redo/split/copy/delete/drag-reorder/zoom,
  subtitle style + per-clip text editor, transition select (xfade preview),
  BGM upload + volume, save draft, export-with-save → shows/download final MP4
- embedded asset URLs everywhere (beat assets pagination)

UX: re-entry guard in action() (no double-submit anywhere) + greyed :disabled
styles for btn-aigen/chat-mode/pill-cta/tl-action so generate buttons visibly
disable while generating.

Also includes prior uncommitted frontend work: settings preferences/sessions/avatar,
asset delete, account/team/products pages, fonts.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/frontend/src/ai-tools-page.css

@@ -239,6 +239,31 @@
   color: var(--black-alpha-48); letter-spacing: .06em;
   text-transform: uppercase;
 }
+/* 新建商品 主 CTA(转写自 model-photo.html .mp-list-h .new-prod) */
+.image-workbench .iw-list-h .new-prod {
+  margin-left: auto;
+  height: 28px; padding: 0 12px 0 10px;
+  display: inline-flex; align-items: center; gap: 6px;
+  background: var(--heat); color: #fff;
+  border: 1px solid var(--heat);
+  border-radius: var(--r-sm);
+  font-size: 12px; font-weight: 600;
+  font-family: inherit; cursor: pointer;
+  box-shadow:
+    inset 0 -2px 4px rgba(250, 93, 25, 0.20),
+    0 1px 1px rgba(250, 93, 25, 0.12),
+    0 2px 4px rgba(250, 93, 25, 0.10);
+  transition: filter var(--t-base), transform var(--t-fast), box-shadow var(--t-base);
+}
+.image-workbench .iw-list-h .new-prod:hover {
+  filter: brightness(.96);
+  box-shadow:
+    inset 0 -2px 4px rgba(250, 93, 25, 0.20),
+    0 1px 1px rgba(250, 93, 25, 0.16),
+    0 4px 8px rgba(250, 93, 25, 0.20);
+}
+.image-workbench .iw-list-h .new-prod:active { transform: scale(.98); }
+.image-workbench .iw-list-h .new-prod svg { width: 12px; height: 12px; }
 .image-workbench .iw-ps-search {
   position: relative; height: 32px;
   margin: 12px 14px 10px;
@@ -359,6 +384,9 @@
   transition: border-color var(--t-base), color var(--t-base);
 }
 .image-workbench .iw-main-h .tb-chip:hover { border-color: var(--heat-20); color: var(--heat); }
+.image-workbench .iw-main-h .tb-chip svg { width: 10px; height: 10px; opacity: .6; }
+.image-workbench .iw-main-h .tb-menu-wrap { position: relative; }
+.image-workbench .iw-main-h .tb-search-wrap { display: inline-flex; align-items: center; }
 .image-workbench .iw-main-body {
   flex: 1; min-height: 0;
   display: grid;
@@ -1493,3 +1521,16 @@
   box-shadow: var(--shadow-cta);
 }
 .model-demo.dm-b .dm-param .gen-btn svg { width: 14px; height: 14px; }
+
+/* ─── 任务中心 · 网格视图(转写自 asset-factory.html .history-grid/.history-card)─── */
+.asset-factory .history-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
+@media (max-width: 1280px) { .asset-factory .history-grid { grid-template-columns: repeat(3, 1fr); } }
+@media (max-width: 960px) { .asset-factory .history-grid { grid-template-columns: repeat(2, 1fr); } }
+.asset-factory .history-card { background: var(--surface); border: 1px solid var(--border-faint); border-radius: var(--r-md); padding: 12px; display: grid; grid-template-columns: 78px 1fr; gap: 14px; align-items: center; transition: background var(--t-base); position: relative; }
+.asset-factory .history-card:hover { background: var(--black-alpha-4); }
+.asset-factory .history-card .placeholder { width: 78px; height: 78px; }
+.asset-factory .history-body { min-width: 0; }
+.asset-factory .history-name { font-weight: 600; color: var(--accent-black); font-size: 13.5px; }
+.asset-factory .history-type { font-size: 11.5px; color: var(--black-alpha-48); margin-top: 3px; font-family: var(--font-mono); letter-spacing: .02em; }
+.asset-factory .history-foot { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-top: 10px; }
+.asset-factory .history-foot .mono { font-family: var(--font-mono); font-size: 10.5px; color: var(--black-alpha-48); }