feat(core): notification inbox infinite scroll + command palette fix (+ pending WIP)

消息中心:全量渲染 → 真·后端分页滚动加载
- backend(ops/views): NotificationPagination(10/页,page_size 可覆盖)+
  响应回 type_counts(按收件人绝对计数,不受分页/搜索影响)
- frontend(messages): 自管分页,滚到底加载下一批;tab/搜索走服务端并重置到第1页;
  代号作废在途旧请求防切换卡空白;乐观标已读;「已加载 X / Y」分母用当前筛选总数
- api/App/types: listNotifications 支持 page/page_size/search;allNotifications 携带 type_counts

命令面板(侧边栏搜索):修复点开后 UI 错位
- app-shell: 遮罩 className 漏了基类 shell-command-bg(只有 .show)致无定位塌到左下;
  补回基类 + header 类名对齐 .shell-command-h
- messages-page.css: 工作台收进视口高度,收件箱在面板内滚动

本次提交一并带入此前若干未提交 WIP(account/ai-tools/library/pipeline/products/settings +
accounts/ai/assets/billing/projects 后端),按用户要求整体推 dev。

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

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

@@ -158,6 +158,8 @@
   font-family: var(--font-mono); font-size: 11px;
   letter-spacing: .04em; margin-bottom: 6px;
 }
+.asset-factory .task-load-more { display: flex; justify-content: center; margin-top: 18px; }
+.asset-factory .task-load-more .lm-rest { font-family: var(--font-mono); font-size: 10.5px; color: var(--black-alpha-48); margin-left: 6px; }
 
 /* ============================================================
    B · 图片工作室壳(.image-workbench)
@@ -1529,6 +1531,11 @@
 .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; }
+/* 任务结果图:有真实生成图时铺满占位框,去掉斜纹底与编号 */
+.asset-factory .placeholder.has-img { overflow: hidden; position: relative; }
+.asset-factory .placeholder.has-img::after { display: none; }
+.asset-factory .placeholder.has-img .ph-frame { display: none; }
+.asset-factory .placeholder.has-img img { width: 100%; height: 100%; object-fit: cover; display: block; }
 .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; }