[Build] Refactor: slim backup_sync_screen by reusing extracted sync widgets

# Diet Ketat untuk Sync Screen: Hasilnya Ramping & Kinclong! ✨ Aku baru saja menyelesaikan satu --- ### Raw Commit Data ## GitHub Update **Repository:** [MKWcorp/POS-DRW-Skincare](https://github.com/MKWcorp/POS-DRW-Skincare) **Author:** multimediadrw **Date:** 5/8/2026, 9:24:34 PM **Commit:** [`4b1baf9`](https://github.com/MKWcorp/POS-DRW-Skincare/commit/4b1baf90acef6bda08a63cbafa44c8b61145624e) ### Commit Message Refactor: slim backup_sync_screen by reusing extracted sync widgets - Use SyncStatusCard widget instead of duplicated _buildStatusCard - Use SyncActionButton widget instead of duplicated _buildSyncButton - Keep account warning + custom header local - File size: 602 -> 426 lines - Replace deprecated withOpacity with withValues --- _This story was imported from historical commits._