Show cached schedule coverage status in admin

lib/data/services/sync_service.dart

@@ -4,6 +4,75 @@ import 'package:intl/intl.dart';
 import '../local/models.dart';
 import 'myquran_service.dart';
 
+class ScheduleCacheStatus {
+  final DateTime? startDate;
+  final DateTime? endDate;
+  final int cachedDays;
+  final int daysUntilRefresh;
+
+  const ScheduleCacheStatus({
+    required this.startDate,
+    required this.endDate,
+    required this.cachedDays,
+    required this.daysUntilRefresh,
+  });
+
+  const ScheduleCacheStatus.empty()
+      : startDate = null,
+        endDate = null,
+        cachedDays = 0,
+        daysUntilRefresh = -1;
+
+  bool get hasData => startDate != null && endDate != null && cachedDays > 0;
+  bool get isExpired => hasData && daysUntilRefresh < 0;
+  bool get needsRefreshSoon => hasData && daysUntilRefresh <= 3;
+
+  static ScheduleCacheStatus fromSchedules(
+    Iterable<DailyPrayerSchedule> schedules,
+    DateTime referenceDate,
+  ) {
+    DateTime? startDate;
+    DateTime? endDate;
+    var cachedDays = 0;
+
+    for (final schedule in schedules) {
+      final parsedDate = DateTime.tryParse(schedule.date);
+      if (parsedDate == null) continue;
+
+      final normalized = DateTime(
+        parsedDate.year,
+        parsedDate.month,
+        parsedDate.day,
+      );
+
+      cachedDays++;
+      startDate = startDate == null || normalized.isBefore(startDate)
+          ? normalized
+          : startDate;
+      endDate = endDate == null || normalized.isAfter(endDate)
+          ? normalized
+          : endDate;
+    }
+
+    if (startDate == null || endDate == null || cachedDays == 0) {
+      return const ScheduleCacheStatus.empty();
+    }
+
+    final today = DateTime(
+      referenceDate.year,
+      referenceDate.month,
+      referenceDate.day,
+    );
+
+    return ScheduleCacheStatus(
+      startDate: startDate,
+      endDate: endDate,
+      cachedDays: cachedDays,
+      daysUntilRefresh: endDate.difference(today).inDays,
+    );
+  }
+}
+
 /// Service to sync monthly prayer data from MyQuran API → Hive.
 class SyncService {
   SyncService._();
@@ -90,4 +159,13 @@ class SyncService {
     final dateStr = DateFormat('yyyy-MM-dd').format(dateToFetch);
     return scheduleBox.get(dateStr);
   }
+
+  ScheduleCacheStatus getCacheStatus([DateTime? referenceDate]) {
+    final scheduleBox =
+        Hive.box<DailyPrayerSchedule>(HiveBoxes.prayerSchedule);
+    return ScheduleCacheStatus.fromSchedules(
+      scheduleBox.values,
+      referenceDate ?? DateTime.now(),
+    );
+  }
 }