refactor: 代码质量清理与日志规范化

- 替换 System.out.println/printStackTrace 为 Logger: MkgsTool, PodTool, WsTool, IpExtractor, ReqIpUtil, LogStatistics
- JsPlaygroundLogger 日志列表限制最大 1000 条防止内存泄漏
- JsScriptLoader JarFile 改用 try-with-resources 防止文件句柄泄漏
- DbServiceImpl Thread.sleep 改为 vertx.setTimer 避免阻塞 event loop
- 删除未使用的 api.js，删除空的 ParserApiClientLinkTest
- 移除前端未使用的导入和死代码 (downloaderService, monacoTypes)
- 提取 previewBaseUrl 到 constants.js 常量文件

web-service/src/main/java/cn/qaiu/lz/common/interceptorImpl/LogStatistics.java

@@ -48,6 +48,6 @@ public class LogStatistics implements AfterInterceptor {
                 .execute(info)
                 .onSuccess(res -> {
                     log.info("inserted log: id={}, path={}, code={}", info.getId(), info.getPath(), info.getCode());
-                }).onFailure(Throwable::printStackTrace);
+                }).onFailure(e -> log.error("插入解析日志失败: id={}", info.getId(), e));
     }
 }

web-service/src/main/java/cn/qaiu/lz/web/service/impl/DbServiceImpl.java

@@ -42,12 +42,11 @@ public class DbServiceImpl implements DbService {
     @Override
     public Future<JsonObject> sayOk(String data) {
         log.info("say ok1 -> wait...");
-        try {
-            Thread.sleep(4000);
-        } catch (InterruptedException e) {
-            e.printStackTrace();
-        }
-        return Future.succeededFuture(JsonObject.mapFrom(JsonResult.data("Hi: " + data)));
+        Promise<JsonObject> promise = Promise.promise();
+        cn.qaiu.vx.core.util.VertxHolder.getVertxInstance().setTimer(4000, id -> {
+            promise.complete(JsonObject.mapFrom(JsonResult.data("Hi: " + data)));
+        });
+        return promise.future();
     }
 
     @Override

web-service/src/test/java/cn/qaiu/lz/web/controller/ParserApiClientLinkTest.java

@@ -1 +0,0 @@
-