feat(core/frontend): ai-tools per-mode layouts (image=chat-stream / model=person picker / cover=platform) + pipeline real unread bell

- ImageWorkbenchPage now renders mode-specific layouts matching each baseline:
  image -> chat-stream (conversation list + hero + prompt chips + chat input bar);
  model -> product rail + 真人模特 cards (assets category=person, fallback Ava/Luna/Mia/Zoe) + per-model count;
  cover -> platform-kit picker. Generation (onGenerate) wiring + loading/empty/fail states preserved.
- pipeline.tsx: bespoke topbar bell now shows real unreadCount (was hardcoded 12); App.tsx threads it.
verified: tsc --noEmit clean; screenshot confirms image-optimize matches chat-stream baseline.

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

core/frontend/src/routes/pipeline.tsx

@@ -62,6 +62,7 @@ export function PipelinePage(props: {
   assets: Asset[];
   billing: BillingSummary | null;
   notice: Notice | null;
+  unreadCount: number;
   avatarChar: string;
   logout: () => void;
   onRefresh: () => void;
@@ -77,7 +78,7 @@ export function PipelinePage(props: {
   onSubmitExport: () => void;
 }) {
   const {
-    project, loading, navigate, user, team, products, projects, assets, billing, notice, avatarChar, logout,
+    project, loading, navigate, user, team, products, projects, assets, billing, notice, unreadCount, avatarChar, logout,
     onGenerateScript, onGenerateBaseAsset, onGenerateStoryboard, onSkipStoryboard,
     onSubmitVideo, onSubmitAllVideos, onSubmitExport
   } = props;
@@ -168,7 +169,7 @@ export function PipelinePage(props: {
             </span>
             <button className="icon-btn" type="button" onClick={() => navigate("messages")} title="消息中心">
               <IconKitSvg name="bell" />
-              <span className="count-noti">12</span>
+              {unreadCount > 0 && <span className="count-noti">{unreadCount}</span>}
             </button>
             <div className="topbar-avatar" onDoubleClick={logout} title="账户(双击退出)">
               <span>{avatarChar}</span>