[Prajwal-4121998]

• Added syncProducts() to ProductRepository interface, returns domain-owned SyncResult
• SyncResult/SyncError: sealed domain types, zero framework deps, replace exception-based failure signaling across the repository boundary
• ProductRepositoryImpl: sole translation boundary, catches real exceptions, maps to SyncError, never throws outward for expected failure cases
• ProductSyncWorker: @HiltWorker CoroutineWorker kept as thin glue only
• SyncResultMapper: pure function extracted for retry/fail decision logic, unit tested independently of WorkManager/Android runtime
• SyncScheduler: encapsulates WorkManager scheduling, UNMETERED (Wi-Fi only) + battery-not-low constraints, 6-hour interval, exponential backoff (15min base), ExistingPeriodicWorkPolicy.KEEP prevents timer reset on repeated schedule calls
• WorkManagerModule: @provides WorkManager singleton via Hilt
• CatalogApplication: implements Configuration.Provider with HiltWorkerFactory, removed default WorkManagerInitializer (required for Hilt worker injection to take effect), schedules sync in onCreate()
• Tests: SyncResultMapperTest covers all retry/fail branches including runAttemptCount boundary; ProductRepositoryImplTest covers syncProducts success and NoInternet error paths