fix: prioritize realtime reminder archive with cold-start fallback

apps/test/features/calendar/reminders/reminder_action_executor_test.dart

@@ -30,6 +30,7 @@ void main() {
       calendarService: calendarService,
       notificationService: notificationService,
       outboxStore: outboxStore,
+      isAppActive: () => true,
     );
   });
 
@@ -57,13 +58,50 @@ void main() {
     expect(pending, isEmpty);
   });
 
-  test('archive failure writes pending outbox item', () async {
+  test(
+    'archive action should send remote archive immediately when app active',
+    () async {
+      when(
+        () => notificationService.cancelEventReminder('evt_live'),
+      ).thenAnswer((_) async {});
+      when(
+        () => calendarService.archiveEvent('evt_live'),
+      ).thenAnswer((_) async => null);
+
+      executor = ReminderActionExecutor(
+        calendarService: calendarService,
+        notificationService: notificationService,
+        outboxStore: outboxStore,
+        isAppActive: () => true,
+      );
+
+      await executor.handleAction(
+        action: ReminderAction.archive,
+        payload: ReminderPayload(
+          eventId: 'evt_live',
+          title: 'sync',
+          startAt: DateTime.parse('2026-03-18T16:00:00+08:00'),
+          timezone: 'Asia/Shanghai',
+        ),
+      );
+
+      verify(() => calendarService.archiveEvent('evt_live')).called(1);
+      final pending = await outboxStore.listPending();
+      expect(pending, isEmpty);
+    },
+  );
+
+  test('archive in inactive app writes pending outbox item', () async {
     when(
       () => notificationService.cancelEventReminder('evt_1'),
     ).thenAnswer((_) async {});
-    when(
-      () => calendarService.archiveEvent('evt_1'),
-    ).thenThrow(Exception('offline'));
+
+    executor = ReminderActionExecutor(
+      calendarService: calendarService,
+      notificationService: notificationService,
+      outboxStore: outboxStore,
+      isAppActive: () => false,
+    );
 
     await executor.handleAction(
       action: ReminderAction.archive,