fix: LzTool/IzToolWithAuth 最后两处 .get().toString() NPE 风险

- LzTool:221 — obj.get("url").toString() 改为 String.valueOf()
- IzToolWithAuth:434 — get("uuid").toString() 添加 null 检查

parser/src/main/java/cn/qaiu/parser/impl/IzToolWithAuth.java

@@ -431,7 +431,8 @@ public class IzToolWithAuth extends PanBase {
         // 如果参数里的目录ID不为空，则直接解析目录
         String dirId = (String) shareLinkInfo.getOtherParam().get("dirId");
         if (dirId != null && !dirId.isEmpty()) {
-            uuid = shareLinkInfo.getOtherParam().get("uuid").toString();
+            Object uuidObj = shareLinkInfo.getOtherParam().get("uuid");
+            uuid = uuidObj != null ? uuidObj.toString() : null;
             parserDir(dirId, shareId, promise);
             return promise.future();
         }

parser/src/main/java/cn/qaiu/parser/impl/LzTool.java

@@ -218,7 +218,7 @@ public class LzTool extends PanBase {
             return;
         }
         Map<?, ?> signMap = (Map<?, ?>)obj.get("data");
-        String url0 = obj.get("url").toString();
+        String url0 = String.valueOf(obj.get("url"));
         MultiMap map = MultiMap.caseInsensitiveMultiMap();
         signMap.forEach((k, v) -> {
             map.add((String) k, v.toString());