style: 按 Beat 分组整理镜头目录并去除重复编号

src/admin.css

@@ -461,15 +461,40 @@ body {
     padding: 8px 0 16px;
 }
 .directory-group-heading {
+    position: sticky;
+    top: 0;
+    z-index: 1;
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 12px;
     flex-shrink: 0;
-    padding: 14px 14px 2px;
+    padding: 10px 14px;
+    border-block: 1px solid var(--app-border);
+    background: var(--app-subtle);
     font:
-        11px/1.6 ui-monospace,
+        600 11px/1.6 ui-monospace,
         monospace;
+    color: var(--app-ink);
+}
+.directory-group-count {
+    font-weight: 400;
     color: var(--app-muted);
 }
-.directory-group-heading:first-child {
-    padding-top: 2px;
+.beat-directory-group {
+    min-width: 0;
+}
+.beat-directory-items {
+    display: flex;
+    flex-direction: column;
+}
+.directory-mobile-beat {
+    display: none;
+}
+.shot-list-content,
+.production-shot-list-content {
+    gap: 12px;
+    padding: 0 0 12px;
 }
 .n-button.directory-item {
     display: flex;
@@ -1216,6 +1241,13 @@ body {
     .directory-group-heading {
         display: none;
     }
+    .beat-directory-group,
+    .beat-directory-items {
+        display: contents;
+    }
+    .directory-mobile-beat {
+        display: inline;
+    }
     .identity-workspace {
         grid-template-columns: minmax(0, 1fr);
         grid-template-rows: 250px minmax(0, 1fr);