fix: 支持编辑分类

- 分类项添加编辑按钮
- 悬停时显示编辑按钮
- 点击编辑按钮打开编辑弹窗

frontend/src/App.jsx

@@ -144,10 +144,15 @@ function App() {
           </div>
 
           {categories.map(cat => (
-            <div key={cat.id} className={`category-item ${selectedCategory === cat.id ? 'active' : ''}`} onClick={() => setSelectedCategory(cat.id)}>
-              <div className="category-icon"><Icon name={cat.icon || 'folder'} size={14}/></div>
-              <span className="category-name">{cat.name}</span>
-              <span className="category-count">{getCategoryCount(cat.id)}</span>
+            <div key={cat.id} className="category-item-wrapper">
+              <div className={`category-item ${selectedCategory === cat.id ? 'active' : ''}`} onClick={() => setSelectedCategory(cat.id)}>
+                <div className="category-icon"><Icon name={cat.icon || 'folder'} size={14}/></div>
+                <span className="category-name">{cat.name}</span>
+                <span className="category-count">{getCategoryCount(cat.id)}</span>
+              </div>
+              <button className="category-edit-btn" onClick={(e) => { e.stopPropagation(); openModal('category', cat) }} title="编辑">
+                <Icon name="edit" size={12}/>
+              </button>
             </div>
           ))}
         </div>