fix: upload progress bar flickering (#25829)

* fix: upload progress bar flickering

* pr feedback and more logs

mobile/lib/providers/backup/drift_backup.provider.dart

@@ -259,6 +259,11 @@ class DriftBackupNotifier extends StateNotifier<DriftBackupState> {
   }
 
   Future<void> startForegroundBackup(String userId) async {
+    // Cancel any existing backup before starting a new one
+    if (state.cancelToken != null) {
+      await stopForegroundBackup();
+    }
+
     state = state.copyWith(error: BackupError.none);
 
     final cancelToken = CancellationToken();
@@ -375,21 +380,21 @@ class DriftBackupNotifier extends StateNotifier<DriftBackupState> {
       _logger.warning("Skip handleBackupResume (pre-call): notifier disposed");
       return;
     }
-    _logger.info("Resuming backup tasks...");
+    _logger.info("Start background backup sequence");
     state = state.copyWith(error: BackupError.none);
     final tasks = await _backgroundUploadService.getActiveTasks(kBackupGroup);
     if (!mounted) {
       _logger.warning("Skip handleBackupResume (post-call): notifier disposed");
       return;
     }
-    _logger.info("Found ${tasks.length} tasks");
+    _logger.info("Found ${tasks.length} pending tasks");
 
     if (tasks.isEmpty) {
-      _logger.info("Start backup with URLSession");
+      _logger.info("No pending tasks, starting new upload");
       return _backgroundUploadService.uploadBackupCandidates(userId);
     }
 
-    _logger.info("Tasks to resume: ${tasks.length}");
+    _logger.info("Resuming upload ${tasks.length} assets");
     return _backgroundUploadService.resume();
   }
 }

mobile/lib/services/background_upload.service.dart

@@ -164,9 +164,12 @@ class BackgroundUploadService {
 
     final candidates = await _backupRepository.getCandidates(userId);
     if (candidates.isEmpty) {
+      _logger.info("No new backup candidates found, finishing background upload");
       return;
     }
 
+    _logger.info("Found ${candidates.length} backup candidates for background tasks");
+
     const batchSize = 100;
     final batch = candidates.take(batchSize).toList();
     List<UploadTask> tasks = [];
@@ -179,6 +182,7 @@ class BackgroundUploadService {
     }
 
     if (tasks.isNotEmpty && !shouldAbortQueuingTasks) {
+      _logger.info("Enqueuing ${tasks.length} background upload tasks");
       await enqueueTasks(tasks);
     }
   }