feat: 删除亲情卡分类并优化搜索功能

- 移除亲情卡支出分类（前端+后端）
- 搜索结果添加点击编辑功能
- 提取 RecordModal 组件复用（index.js/search.js）
- 添加 useMemo 优化计算性能
- 优化类别查找为 O(1) 映射
- 添加删除分类接口输入验证

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server.js

@@ -384,6 +384,20 @@ app.delete('/api/records/:id', authenticate, (req, res) => {
   res.json({ message: '删除成功' });
 });
 
+// 批量删除指定分类的记录
+app.delete('/api/records/by-category/:category', authenticate, (req, res) => {
+  const { category } = req.params;
+
+  if (!category || typeof category !== 'string' || !category.trim()) {
+    return res.status(400).json({ error: '分类不能为空' });
+  }
+
+  const stmt = db.prepare('DELETE FROM records WHERE category = ? AND user_id = ?');
+  const result = stmt.run(category.trim(), req.userId);
+
+  res.json({ message: `已删除 ${result.changes} 条记录` });
+});
+
 // 获取月度统计
 app.get('/api/stats', authenticate, (req, res) => {
   const { month } = req.query;
@@ -630,7 +644,6 @@ app.get('/api/categories', authenticate, (req, res) => {
       { name: '娱乐', icon: '🎮' },
       { name: '房租', icon: '🏠' },
       { name: '房贷', icon: '🏦' },
-      { name: '亲情卡', icon: '💳' },
       { name: '水电', icon: '💧' },
       { name: '衣服', icon: '👔' },
       { name: '通讯', icon: '📱' },