feat: automatically reconcile offline sync on startup and resume

lib/services/sync/sync_manager.dart

@@ -1,16 +1,22 @@
 import 'dart:async';
 import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
 import 'sync_models.dart';
 import 'sync_outbox.dart';
 import 'sync_provider.dart';
 
 /// Central provider-agnostic synchronization coordinator.
-class SyncManager extends ChangeNotifier {
+///
+/// Sync work is persisted in [SyncOutbox]. The manager also reconciles on
+/// startup, app resume, and periodically while the app is foregrounded so a
+/// ride recorded offline is automatically retried after connectivity returns.
+class SyncManager extends ChangeNotifier with WidgetsBindingObserver {
   final SyncOutbox _outbox;
   final Map<String, SyncProvider> _providers = {};
   String _activeProviderId = 'fake';
   bool _isProcessing = false;
   DateTime? Function() _nowProvider;
+  Timer? _foregroundRetryTimer;
 
   SyncManager(this._outbox, {List<SyncProvider>? initialProviders, String? defaultProviderId, DateTime? Function()? nowProvider}) : _nowProvider = nowProvider ?? (() => DateTime.now()) {
     if (initialProviders != null) {
@@ -19,6 +25,9 @@ class SyncManager extends ChangeNotifier {
       }
     }
     if (defaultProviderId != null) _activeProviderId = defaultProviderId;
+    WidgetsBinding.instance.addObserver(this);
+    _foregroundRetryTimer = Timer.periodic(const Duration(seconds: 30), (_) => unawaited(processQueue()));
+    unawaited(processQueue());
   }
 
   void setNowProvider(DateTime? Function() provider) => _nowProvider = provider;
@@ -63,8 +72,6 @@ class SyncManager extends ChangeNotifier {
     return item;
   }
 
-  /// Enqueues every local ride for the selected cloud provider. Existing
-  /// synced/queued items remain idempotent and are not duplicated.
   Future<int> backupAllRideIds(Iterable<int> rideIds, {String? targetProviderId}) async {
     var enqueued = 0;
     for (final rideId in rideIds) {
@@ -75,7 +82,6 @@ class SyncManager extends ChangeNotifier {
     return enqueued;
   }
 
-  /// Rearms authentication-blocked work. Call this after a successful login/link.
   Future<void> retryAuthRequired() async {
     for (final item in _outbox.getAllItems().where((i) => i.status == SyncStatus.authRequired)) {
       await _outbox.update(item.copyWith(status: SyncStatus.queued, clearLastError: true, clearNextRetry: true));
@@ -94,14 +100,20 @@ class SyncManager extends ChangeNotifier {
     }
   }
 
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    if (state == AppLifecycleState.resumed) {
+      unawaited(processQueue());
+    }
+  }
+
   Future<void> processQueue() async {
     if (_isProcessing) return;
     _isProcessing = true;
     notifyListeners();
     try {
       final now = _now();
-      final eligibleItems = _outbox.getEligibleItems(now);
+      for (final item in _outbox.getEligibleItems(now)) {
-      for (final item in eligibleItems) {
         final provider = _providers[item.providerId];
         if (provider == null) {
           await _outbox.update(item.copyWith(status: SyncStatus.failed, lastError: 'Provider "${item.providerId}" not registered', lastAttemptAt: now));
@@ -115,18 +127,14 @@ class SyncManager extends ChangeNotifier {
           await _outbox.update(item.copyWith(status: SyncStatus.authRequired, lastError: 'Authentication required for provider "${item.providerId}"', lastAttemptAt: now));
           continue;
         }
-
         final uploadingItem = item.copyWith(status: SyncStatus.uploading, lastAttemptAt: now);
         await _outbox.update(uploadingItem);
-        notifyListeners();
-
         SyncResult result;
         try {
           result = await provider.uploadRide(uploadingItem);
         } catch (e) {
           result = SyncResult.temporaryFailure('Unhandled provider exception: $e', timestamp: now);
         }
-
         if (result.success) {
           await _outbox.update(uploadingItem.copyWith(status: SyncStatus.synced, remoteId: result.remoteId, uploadedAt: result.timestamp, clearLastError: true, clearNextRetry: true));
         } else if (result.requiresAuth) {
@@ -152,8 +160,6 @@ class SyncManager extends ChangeNotifier {
     }
   }
 
-  /// Re-arms retryable/pending work and terminal failures. Failed items are
-  /// intentionally retained until the retry is explicitly requested.
   Future<void> retryAllPending() async {
     final retryable = _outbox.getAllItems().where((i) => i.status.isPending || i.status == SyncStatus.failed).toList(growable: false);
     for (final item in retryable) {
@@ -161,4 +167,11 @@ class SyncManager extends ChangeNotifier {
     }
     await processQueue();
   }
+
+  @override
+  void dispose() {
+    _foregroundRetryTimer?.cancel();
+    WidgetsBinding.instance.removeObserver(this);
+    super.dispose();
+  }
 }