feat: 添加数据库支持，保存测算记录

- 添加Spring Data JPA和H2/MySQL数据库依赖
- 创建DeductRecord实体类，保存测算记录
- 创建DeductRecordRepository和DeductRecordService
- 创建RecordController，提供记录查询和删除API
- 修改BaZiController，保存测算结果到数据库
- 配置H2数据库用于开发，MySQL用于生产环境

src/main/java/xuan/service/DeductRecordService.java

@@ -0,0 +1,49 @@
+package xuan.service;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import xuan.entity.DeductRecord;
+import xuan.repository.DeductRecordRepository;
+
+import java.util.List;
+import java.util.Optional;
+
+@Service
+public class DeductRecordService {
+    
+    @Autowired
+    private DeductRecordRepository recordRepository;
+    
+    @Transactional
+    public DeductRecord saveRecord(DeductRecord record) {
+        return recordRepository.save(record);
+    }
+    
+    public Optional<DeductRecord> findById(Long id) {
+        return recordRepository.findById(id);
+    }
+    
+    public List<DeductRecord> findByUserId(String userId) {
+        return recordRepository.findByUserIdOrderByCreateTimeDesc(userId);
+    }
+    
+    public List<DeductRecord> findByUserIdAndType(String userId, String type) {
+        return recordRepository.findByUserIdAndTypeOrderByCreateTimeDesc(userId, type);
+    }
+    
+    public List<DeductRecord> findRecentByUserId(String userId) {
+        return recordRepository.findTop10ByUserIdOrderByCreateTimeDesc(userId);
+    }
+    
+    @Transactional
+    public void deleteById(Long id) {
+        recordRepository.deleteById(id);
+    }
+    
+    @Transactional
+    public void deleteByUserId(String userId) {
+        List<DeductRecord> records = recordRepository.findByUserIdOrderByCreateTimeDesc(userId);
+        recordRepository.deleteAll(records);
+    }
+}