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/styles.css

@@ -54,6 +54,47 @@ html, body, #app {
   color: #1a1a1a;
 }
 
+.page-title-card {
+  background: #fff;
+  border: 1px solid #e6edf5;
+  border-radius: 12px;
+  overflow: hidden;
+}
+
+.page-title-card__header {
+  display: flex;
+  align-items: flex-start;
+  justify-content: space-between;
+  gap: 24px;
+  padding: 24px;
+}
+
+.page-title-card__copy {
+  min-width: 0;
+}
+
+.page-title-card__copy h2 {
+  margin: 0;
+  color: #1a1a1a;
+  font-size: 20px;
+  font-weight: 600;
+  line-height: 1.4;
+}
+
+.page-title-card__copy p {
+  margin: 6px 0 0;
+  color: #8c8c8c;
+  font-size: 13px;
+  line-height: 1.7;
+}
+
+.page-title-card__actions {
+  flex-shrink: 0;
+  display: flex;
+  align-items: center;
+  gap: 12px;
+}
+
 .table-actions-row {
   display: flex;
   align-items: center;