feat: add local-first private AI digest workflow

Migrate app code into canonical feature slices, add phone-only AI digest scheduling and review, wire local notification/background task support, and cover the flow with tests.

lib/features/reminders/scheduling/reminder_scheduler.dart

@@ -1,27 +1,2 @@
-import 'package:relationship_saver/features/local/local_models.dart';
-
-/// Schedules and reconciles reminder deliveries for current local state.
-abstract class ReminderScheduler {
-  /// Reconciles platform schedules to match current enabled reminders.
-  Future<void> reconcile(List<ReminderRule> reminders);
-
-  /// Clears all platform-scheduled reminder jobs.
-  Future<void> clearAll();
-
-  /// Requests notification permissions where the platform requires them.
-  Future<bool> requestPermissions();
-}
-
-/// Default scheduler used until platform notifications are integrated.
-class NoopReminderScheduler implements ReminderScheduler {
-  const NoopReminderScheduler();
-
-  @override
-  Future<void> clearAll() async {}
-
-  @override
-  Future<void> reconcile(List<ReminderRule> reminders) async {}
-
-  @override
-  Future<bool> requestPermissions() async => true;
-}
+// Legacy compatibility export for the reminders scheduling service.
+export 'package:relationship_saver/features/reminders/application/reminder_scheduler.dart';