修复分类编辑弹窗内按钮触发表单提交导致跳转首页的问题 (v2.2.1)

- 根因: 编辑分类弹窗里的子类别/参数字段列表按钮渲染在 <form id=itemForm> 内且无 type=button，HTML 按钮默认 type=submit，点击时同时触发表单 GET 提交 → 页面刷新跳转到 /admin 首页
- 修复: 给 renderSubcategoriesList/renderFieldsList 的编辑/删除按钮、getImageUploadComponent 的图片操作按钮补 type=button
- 加固: 全局拦截 itemForm 原生 submit (preventDefault)，保存统一走 saveItem，杜绝同类按钮再次引发页面跳转

templates/admin.html

@@ -1586,7 +1586,7 @@
                         ${imageUrls.map((url, idx) => `
                             <div class="relative w-24 h-24 border rounded-lg overflow-hidden group">
                                 <img src="${url}" class="w-full h-full object-cover">
-                                <button onclick="removeImage(${idx})" class="absolute top-1 right-1 w-6 h-6 bg-red-500 text-white rounded-full opacity-0 group-hover:opacity-100 transition flex items-center justify-center">
+                                <button type="button" onclick="removeImage(${idx})" class="absolute top-1 right-1 w-6 h-6 bg-red-500 text-white rounded-full opacity-0 group-hover:opacity-100 transition flex items-center justify-center">
                                     <i class="ri-close-line"></i>
                                 </button>
                             </div>
@@ -1594,10 +1594,10 @@
                     </div>
                     <div class="flex gap-2">
                         <input type="file" id="imageInput" accept="image/*" multiple class="hidden" onchange="handleImageUpload(event, '${type}')">
-                        <button onclick="document.getElementById('imageInput').click()" class="px-4 py-2 bg-gray-100 text-gray-600 rounded-lg hover:bg-gray-200 text-sm">
+                        <button type="button" onclick="document.getElementById('imageInput').click()" class="px-4 py-2 bg-gray-100 text-gray-600 rounded-lg hover:bg-gray-200 text-sm">
                             <i class="ri-image-add-line mr-1"></i>选择图片
                         </button>
-                        <button onclick="pasteImageFromClipboard('${type}')'" class="px-4 py-2 bg-gray-100 text-gray-600 rounded-lg hover:bg-gray-200 text-sm">
+                        <button type="button" onclick="pasteImageFromClipboard('${type}')'" class="px-4 py-2 bg-gray-100 text-gray-600 rounded-lg hover:bg-gray-200 text-sm">
                             <i class="ri-clipboard-line mr-1"></i>粘贴图片
                         </button>
                     </div>
@@ -1843,10 +1843,10 @@
                         </div>
                     </div>
                     <div class="flex gap-2 opacity-0 group-hover:opacity-100 transition">
-                        <button onclick="editSubcategory(${index})" class="px-2 py-1 text-blue-600 hover:bg-blue-50 rounded text-sm">
+                        <button type="button" onclick="editSubcategory(${index})" class="px-2 py-1 text-blue-600 hover:bg-blue-50 rounded text-sm">
                             <i class="ri-edit-line"></i>
                         </button>
-                        <button onclick="deleteSubcategory(${index})" class="px-2 py-1 text-red-600 hover:bg-red-50 rounded text-sm">
+                        <button type="button" onclick="deleteSubcategory(${index})" class="px-2 py-1 text-red-600 hover:bg-red-50 rounded text-sm">
                             <i class="ri-delete-bin-line"></i>
                         </button>
                     </div>
@@ -1884,10 +1884,10 @@
                         </div>
                     </div>
                     <div class="flex gap-2 opacity-0 group-hover:opacity-100 transition">
-                        <button onclick="editField(${index})" class="px-2 py-1 text-blue-600 hover:bg-blue-50 rounded text-sm">
+                        <button type="button" onclick="editField(${index})" class="px-2 py-1 text-blue-600 hover:bg-blue-50 rounded text-sm">
                             <i class="ri-edit-line"></i>
                         </button>
-                        <button onclick="deleteField(${index})" class="px-2 py-1 text-red-600 hover:bg-red-50 rounded text-sm">
+                        <button type="button" onclick="deleteField(${index})" class="px-2 py-1 text-red-600 hover:bg-red-50 rounded text-sm">
                             <i class="ri-delete-bin-line"></i>
                         </button>
                     </div>
@@ -2239,6 +2239,13 @@
         document.getElementById('smartUpdateModal').addEventListener('click', function(e) { if (e.target === this) closeSmartUpdateModal(); });
         document.getElementById('fieldModal').addEventListener('click', function(e) { if (e.target === this) closeFieldModal(); });
 
+        // 防止 itemForm 原生提交（保存统一走 saveItem，避免表单 GET 提交导致页面跳转/刷新）
+        document.addEventListener('submit', function(e) {
+            if (e.target && e.target.id === 'itemForm') {
+                e.preventDefault();
+            }
+        });
+
         // ============ 智能添加功能 ============
         
         let smartAddType = '';