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/en-US.ts

@@ -211,6 +211,7 @@ const enUS = {
     },
     manage: {
       title: "KOL Prompt Management",
+      subtitle: "Manage refined template packages, prompts, platforms, variables, and publishing status.",
       packageTitle: "Packages",
       promptTitle: "Prompts",
       createPackage: "Create package",
@@ -295,6 +296,7 @@ const enUS = {
     },
     dashboard: {
       title: "KOL Dashboard",
+      subtitle: "Track subscriptions and generation metrics in real time.",
       totalSubs: "Total subscribed tenants",
       monthSubs: "New this month",
       totalUsage: "Total usage",