fix(bugcollect): 修复 callSymbolicator 字段名 sourcemap → mappingFile

Android symbolicator API 期望 mappingFile 字段，之前误用 sourcemap 导致
符号化返回 "mappingFile is required for Android" 错误，堆栈无法还原。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

xuqm-bugcollect-service/src/main/java/com/xuqm/bugcollect/service/LogService.java

@@ -210,7 +210,7 @@ public class LogService {
             java.util.Map<String, Object> request = java.util.Map.of(
                 "platform", platform,
                 "stacktrace", stacktrace,
-                "sourcemap", sourcemapContent
+                "mappingFile", sourcemapContent
             );
 
             org.springframework.http.HttpHeaders headers = new org.springframework.http.HttpHeaders();