refactor(admin-web): unify page headers with shared title card

Introduce .page-title-card style and migrate Images, Knowledge,
KolDashboard, KolManage, KolProfile views to the shared header layout.
Add subtitle copy for KOL dashboard and manage views.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/admin-web/src/i18n/messages/zh-CN.ts

@@ -211,6 +211,7 @@ const zhCN = {
     },
     manage: {
       title: "KOL 提示词管理",
+      subtitle: "管理精调模版订阅包与提示词，配置平台、变量和上下线状态。",
       packageTitle: "订阅包",
       promptTitle: "提示词",
       createPackage: "创建订阅包",
@@ -295,6 +296,7 @@ const zhCN = {
     },
     dashboard: {
       title: "KOL 数据看板",
+      subtitle: "实时查看订阅情况与生成数据统计。",
       totalSubs: "总订阅租户数",
       monthSubs: "本月新增",
       totalUsage: "总使用次数",