refactor(apps): 重构数据层目录结构并新增启动预热编排器

apps/test/data/cache/cached_repository_test.dart

@@ -1,9 +1,7 @@
 import 'package:flutter_test/flutter_test.dart';
 import 'package:social_app/data/cache/cache_policy.dart';
 import 'package:social_app/data/cache/cached_repository.dart';
-import 'package:social_app/data/cache/hybrid_cache_store.dart';
-import 'package:social_app/data/cache/memory_cache_store.dart';
-import 'package:social_app/data/cache/persistent_cache_store.dart';
+import 'package:social_app/data/cache/cache_store.dart';
 
 class _IntCachedRepository extends CachedRepository<int> {
   int loadCount = 0;

apps/test/data/cache/hybrid_cache_store_test.dart

@@ -0,0 +1,28 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'package:social_app/data/cache/cache_store.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  group('HybridCacheStore', () {
+    test('falls back to persistent and backfills memory', () async {
+      SharedPreferences.setMockInitialValues(<String, Object>{});
+      final prefs = await SharedPreferences.getInstance();
+      final persistent = PersistentCacheStore(prefs: prefs);
+      await persistent.write<String>('k', 'v');
+
+      final hybrid = HybridCacheStore(
+        memory: MemoryCacheStore(),
+        persistent: persistent,
+      );
+
+      final firstRead = await hybrid.read<String>('k');
+      expect(firstRead, 'v');
+
+      await persistent.remove('k');
+      final secondRead = await hybrid.read<String>('k');
+      expect(secondRead, 'v');
+    });
+  });
+}

apps/test/data/cache/shared_prefs_cache_store_test.dart

@@ -0,0 +1,39 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'package:social_app/data/cache/cache_store.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  group('SharedPrefsCacheStore', () {
+    test('persists entries across instances', () async {
+      SharedPreferences.setMockInitialValues(<String, Object>{});
+      final prefs = await SharedPreferences.getInstance();
+
+      final storeA = SharedPrefsCacheStore(prefs: prefs);
+      await storeA.write<String>('k', 'v');
+
+      final storeB = SharedPrefsCacheStore(prefs: prefs);
+      final value = await storeB.read<String>('k');
+      expect(value, 'v');
+    });
+
+    test('reads cache entry persisted payload', () async {
+      SharedPreferences.setMockInitialValues(<String, Object>{});
+      final prefs = await SharedPreferences.getInstance();
+      final now = DateTime.utc(2026, 3, 29, 12, 0, 0);
+
+      final storeA = SharedPrefsCacheStore(prefs: prefs);
+      await storeA.write<CacheEntry<String>>(
+        'entry',
+        CacheEntry<String>(value: 'payload', fetchedAt: now),
+      );
+
+      final storeB = SharedPrefsCacheStore(prefs: prefs);
+      final entry = await storeB.read<CacheEntry<String>>('entry');
+      expect(entry, isNotNull);
+      expect(entry!.value, 'payload');
+      expect(entry.fetchedAt, now);
+    });
+  });
+}