feat: 轮播标签功能 — 后台加标签字段 + 多色平行四边形

后台:
- 轮播表单新增: 标签(逗号分隔) / 跳转链接 / 按钮文字 / 按钮链接
- 标签字段提示: 云计算,高性价比,弹性伸缩

前台 CSS:
- 标签改为左对齐
- 6 种渐变色自动轮换: 蓝紫/粉红/绿/金/橙/紫
- 保持平行四边形 skewX + 发光效果

plugins/addon/theme_configurator/template/admin/index.html

@@ -418,6 +418,10 @@
               <label>标题</label>
               <input type="text" class="form-control" data-banner="${index}" data-field="title" value="${banner.title || ''}" placeholder="弹性算力">
             </div>
+            <div class="form-item">
+              <label>标签（逗号分隔）</label>
+              <input type="text" class="form-control" data-banner="${index}" data-field="tags" value="${banner.tags || ''}" placeholder="云计算,高性价比,弹性伸缩">
+            </div>
             <div class="form-item">
               <label>描述</label>
               <input type="text" class="form-control" data-banner="${index}" data-field="description" value="${banner.description || ''}" placeholder="宣传语">
@@ -429,6 +433,18 @@
                 <button class="btn btn-secondary upload-btn" data-target-banner="${index}.img">选择文件</button>
               </div>
             </div>
+            <div class="form-item">
+              <label>跳转链接</label>
+              <input type="text" class="form-control" data-banner="${index}" data-field="url" value="${banner.url || ''}" placeholder="/cloud.html">
+            </div>
+            <div class="form-item">
+              <label>按钮文字</label>
+              <input type="text" class="form-control" data-banner="${index}" data-field="button_text" value="${banner.button_text || ''}" placeholder="立即查看">
+            </div>
+            <div class="form-item">
+              <label>按钮链接</label>
+              <input type="text" class="form-control" data-banner="${index}" data-field="button_link" value="${banner.button_link || ''}" placeholder="/cloud.html">
+            </div>
           </div>
         </div>
       `;