refactor: 代码质量优化 + 安全修复 + 性能提升

P0 安全修复:
- 修复 DatabaseFieldAdder.java 硬编码密码 → 改为环境变量
- 修复 11 个文件空 catch 块 → 添加日志记录
- 修复 40 个文件 System.out → 改为 SLF4J Logger

P1 性能优化:
- 启用 Spring Boot Actuator 健康检查 (health/info/metrics)
- 为字典数据查询添加 @Cacheable 缓存

P2 测试:
- 添加 Convert 工具类单元测试 (10 个测试用例)
- 添加 spring-boot-starter-test 依赖

P3 版本升级:
- hutool: 5.8.35 → 5.8.36
- httpclient 5.x (跳过, 改动量大)

验证: 编译通过 / 测试通过

openhis-server-new/openhis-miniapp/src/main/java/com/openhis/OpenHisMiniApp.java

@@ -1,5 +1,8 @@
 package com.openhis;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 
@@ -11,6 +14,7 @@ import org.springframework.core.env.Environment;
 
 @SpringBootApplication(exclude = {DataSourceAutoConfiguration.class}, scanBasePackages = {"com.core", "com.openhis"})
 public class OpenHisMiniApp {
+    private static final Logger log = LoggerFactory.getLogger(OpenHisMiniApp.class);
     public static void main(String[] args) throws UnknownHostException {
         // System.setProperty("spring.devtools.restart.enabled", "false");
         ConfigurableApplicationContext application = SpringApplication.run(OpenHisMiniApp.class, args);
@@ -18,7 +22,7 @@ public class OpenHisMiniApp {
         String ip = InetAddress.getLocalHost().getHostAddress();
         String port = env.getProperty("server.port");
         String path = env.getProperty("server.servlet.context-path");
-        System.out.println("\n----------------------------------------------------------\n\t"
+        log.info("\n----------------------------------------------------------\n\t"
             + "Application OpenHis is running! Access URLs:\n\t" + "Local: \t\thttp://localhost:" + port + path
             + "/\n\t" + "External: \thttp://" + ip + ":" + port + path + "/\n"
             + "----------------------------------------------------------");