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/core-admin/src/main/java/com/core/web/controller/system/SysConfigController.java

@@ -1,5 +1,8 @@
 package com.core.web.controller.system;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import com.core.common.annotation.Log;
 import com.core.common.core.controller.BaseController;
 import com.core.common.core.domain.AjaxResult;
@@ -24,6 +27,7 @@ import java.util.List;
 @RestController
 @RequestMapping("/system/config")
 public class SysConfigController extends BaseController {
+    private static final Logger log = LoggerFactory.getLogger(SysConfigController.class);
     @Autowired
     private ISysConfigService configService;
 
@@ -72,13 +76,13 @@ public class SysConfigController extends BaseController {
         result.put("code", 200);
         result.put("msg", "操作成功");
         result.put("data", configValue); // 明确设置 data 字段，即使值为空字符串
-        System.out.println("=== getConfigKey 调试信息 ===");
-        System.out.println("configKey: " + configKey);
-        System.out.println("configValue: [" + configValue + "]");
-        System.out.println("result.data: " + result.get("data"));
-        System.out.println("result.msg: " + result.get("msg"));
-        System.out.println("result.code: " + result.get("code"));
-        System.out.println("============================");
+        log.info("=== getConfigKey 调试信息 ===");
+        log.info("configKey: " + configKey);
+        log.info("configValue: [" + configValue + "]");
+        log.info("result.data: " + result.get("data"));
+        log.info("result.msg: " + result.get("msg"));
+        log.info("result.code: " + result.get("code"));
+        log.info("============================");
         return result;
     }