feat(it0_app): add detailed logging to VersionChecker for update diagnosis

Add verbose debugPrint logs throughout VersionChecker to diagnose why
app update check isn't triggering:
- Log apiBaseUrl and full request URL + query params before the request
- Log response status code and raw response body
- Log explicit needUpdate=true/false with version details
- Log version code comparison (server versionCode vs local buildNumber)
- Add stack trace to all catch blocks for better error diagnosis

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

it0_app/lib/core/updater/version_checker.dart

@@ -25,29 +25,38 @@ class VersionChecker {
   Future<VersionInfo?> fetchLatestVersion() async {
     try {
       final currentInfo = await getCurrentVersion();
-      debugPrint('[VersionChecker] 当前版本: ${currentInfo.version}, buildNumber: ${currentInfo.buildNumber}');
+      debugPrint('[VersionChecker] apiBaseUrl: $apiBaseUrl');
+      debugPrint('[VersionChecker] 当前版本: ${currentInfo.version}, buildNumber: ${currentInfo.buildNumber}, packageName: ${currentInfo.packageName}');
+
+      final queryParams = {
+        'platform': 'android',
+        'current_version': currentInfo.version,
+        'current_version_code': currentInfo.buildNumber,
+      };
+      debugPrint('[VersionChecker] 请求: GET $apiBaseUrl/api/app/version/check $queryParams');
 
       final response = await _dio.get(
         '/api/app/version/check',
-        queryParameters: {
-          'platform': 'android',
-          'current_version': currentInfo.version,
-          'current_version_code': currentInfo.buildNumber,
-        },
+        queryParameters: queryParams,
       );
 
+      debugPrint('[VersionChecker] 响应状态: ${response.statusCode}');
+      debugPrint('[VersionChecker] 响应内容: ${response.data}');
+
       if (response.statusCode == 200 && response.data != null) {
         final needUpdate = response.data['needUpdate'] as bool? ?? true;
         if (!needUpdate) {
-          debugPrint('[VersionChecker] 服务器返回无需更新');
+          debugPrint('[VersionChecker] 服务器返回 needUpdate=false，无需更新');
           return null;
         }
-        debugPrint('[VersionChecker] 服务器返回需要更新');
+        debugPrint('[VersionChecker] 服务器返回 needUpdate=true，最新版本: ${response.data['version']} (versionCode=${response.data['versionCode']})');
         return VersionInfo.fromJson(response.data);
       }
+      debugPrint('[VersionChecker] 异常状态码: ${response.statusCode}');
       return null;
-    } catch (e) {
+    } catch (e, stack) {
       debugPrint('[VersionChecker] 获取版本失败: $e');
+      debugPrint('[VersionChecker] StackTrace: $stack');
       return null;
     }
   }
@@ -61,13 +70,17 @@ class VersionChecker {
       if (latestInfo == null) return null;
 
       final currentCode = int.tryParse(currentInfo.buildNumber) ?? 0;
+      debugPrint('[VersionChecker] 版本比较: 服务器 versionCode=${latestInfo.versionCode} vs 本地 buildNumber=$currentCode');
       if (latestInfo.versionCode > currentCode) {
+        debugPrint('[VersionChecker] 有新版本可更新');
         return latestInfo;
       }
 
+      debugPrint('[VersionChecker] 本地版本不低于服务器版本，无需更新');
       return null;
-    } catch (e) {
-      debugPrint('Check update failed: $e');
+    } catch (e, stack) {
+      debugPrint('[VersionChecker] checkForUpdate 异常: $e');
+      debugPrint('[VersionChecker] StackTrace: $stack');
       return null;
     }
   }