fix(admin-web): add custom popup class for knowledge group tree dropdown

apps/admin-web/src/views/KnowledgeView.vue

@@ -719,6 +719,7 @@ function closeItemDetail(): void {
             tree-default-expand-all
             style="width: 240px"
             placeholder="请选择分组目录"
+            popup-class-name="knowledge-group-tree-dropdown"
           />
         </div>
       </div>
@@ -896,6 +897,10 @@ function closeItemDetail(): void {
   margin-top: 4px;
 }
 
+:global(.knowledge-group-tree-dropdown) {
+  z-index: 3102 !important;
+}
+
 .knowledge-url-hint {
   margin-top: 8px;
   color: #6b7280;