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/resources/application.properties

@@ -1,2 +1,30 @@
 server.port=8080
 spring.application.name=xuan-utils-pro
+
+# H2 Database Configuration (Development)
+spring.datasource.url=jdbc:h2:file:./data/xuan;DB_CLOSE_ON_EXIT=FALSE;AUTO_RECONNECT=TRUE
+spring.datasource.driverClassName=org.h2.Driver
+spring.datasource.username=sa
+spring.datasource.password=
+
+# JPA Configuration
+spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
+spring.jpa.hibernate.ddl-auto=update
+spring.jpa.show-sql=true
+spring.jpa.properties.hibernate.format_sql=true
+
+# H2 Console (Development only)
+spring.h2.console.enabled=true
+spring.h2.console.path=/h2-console
+
+# MySQL Configuration (Production - uncomment when needed)
+#spring.datasource.url=jdbc:mysql://localhost:3306/xuan_deduct?useSSL=false&serverTimezone=Asia/Shanghai&characterEncoding=utf8
+#spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
+#spring.datasource.username=root
+#spring.datasource.password=your_password
+#spring.jpa.database-platform=org.hibernate.dialect.MySQL8Dialect
+#spring.jpa.hibernate.ddl-auto=update
+
+# Logging
+logging.level.xuan=DEBUG
+logging.level.org.hibernate.SQL=DEBUG