feat: 帮助文档及首页支持链接自定义

backend/src/main/java/io/dataease/service/panel/PanelLinkService.java

@@ -35,7 +35,7 @@ public class PanelLinkService {
     private static final String USERPARAM = "&user=";
     private static final String SHORT_URL_PREFIX = "/link/";
 
-    @Value("${server.servlet.context-path}")
+    @Value("${server.servlet.context-path:#{null}}")
     private String contextPath;
 
     @Resource