fix(ui): disable token panel expand on mobile tap

- 移动端禁用点击展开顶部用量面板
- 仅允许在已展开时点击收起

static/src/app/methods/ui.ts

@@ -628,7 +628,9 @@ export const uiMethods = {
   },
 
   async changePermissionMode(mode) {
-    const target = String(mode || '').trim().toLowerCase();
+    const target = String(mode || '')
+      .trim()
+      .toLowerCase();
     if (!target || target === this.currentPermissionMode) {
       this.closePermissionMenu();
       return;
@@ -825,6 +827,10 @@ export const uiMethods = {
     if (this.isPolicyBlocked('block_token_panel', '用量统计已被管理员禁用')) {
       return;
     }
+    // 移动端禁用“点击展开顶部用量面板”，仅允许在已展开时点击收起
+    if (this.isMobileViewport && this.tokenPanelCollapsed) {
+      return;
+    }
     this.toggleTokenPanel();
   },