Refresh cached training catalog safely

mobile/lib/services/training_plan_service.dart

@@ -15,12 +15,14 @@ class TrainingPlanService {
   final AuthService _auth;
   final http.Client _client;
 
+  Future<List<TrainingPlan>> readCachedPlans() async {
+    final prefs = await SharedPreferences.getInstance();
+    return _decodeCache(prefs.getString(_cacheKey));
+  }
+
   Future<TrainingCatalogResult> fetchPlans({bool refresh = false}) async {
     final prefs = await SharedPreferences.getInstance();
     final cached = _decodeCache(prefs.getString(_cacheKey));
-    if (!refresh && cached.isNotEmpty) {
-      return TrainingCatalogResult(plans: cached, fromCache: true);
-    }
     if (!_auth.isApiConfigured) {
       return TrainingCatalogResult(
         plans: cached,
@@ -46,6 +48,15 @@ class TrainingPlanService {
           .map(TrainingPlan.fromJson)
           .where((plan) => plan.uuid.isNotEmpty)
           .toList(growable: false);
+      // An empty catalog can be an unpublished/temporarily incomplete response.
+      // Keep the last known good catalog rather than erasing offline content.
+      if (plans.isEmpty && cached.isNotEmpty) {
+        return TrainingCatalogResult(
+          plans: cached,
+          fromCache: true,
+          message: 'لا توجد خطط منشورة حاليًا؛ نعرض آخر نسخة محفوظة.',
+        );
+      }
       await prefs.setString(
         _cacheKey,
         jsonEncode(plans.map(_toCacheJson).toList(growable: false)),