fix: correct test failures and error propagation

- Add CacheScope provider in UserProfileCacheRepository tests
- Remove catch blocks that swallowed errors in _loadHistory/_loadMoreHistory
- Errors now properly propagate to switchUser() caller

apps/test/features/settings/data/repositories/user_profile_cache_repository_test.dart

@@ -1,6 +1,7 @@
 import 'dart:async';
 
 import 'package:flutter_test/flutter_test.dart';
+import 'package:social_app/data/cache/cache_scope.dart';
 import 'package:social_app/data/cache/cache_store.dart';
 import 'package:social_app/features/contacts/data/models/user_profile.dart';
 import 'package:social_app/features/settings/data/repositories/user_profile_cache_repository.dart';
@@ -8,6 +9,8 @@ import 'package:social_app/features/settings/data/repositories/user_profile_cach
 void main() {
   group('UserProfileCacheRepository', () {
     test('keeps in-memory snapshot and invalidates correctly', () async {
+      CacheScope.configureProvider(() => 'test-scope');
+      addTearDown(() => CacheScope.resetProvider());
       var remoteCalls = 0;
       final repository = UserProfileCacheRepository(
         store: HybridCacheStore(
@@ -40,6 +43,9 @@ void main() {
     test(
       'invalidate prevents stale in-flight refresh from restoring cache',
       () async {
+        CacheScope.configureProvider(() => 'test-scope-2');
+        addTearDown(() => CacheScope.resetProvider());
+
         final completer = Completer<UserProfile>();
         final repository = UserProfileCacheRepository(
           store: HybridCacheStore(