Changes: - Constants.kt: Add SYNC_ONSAVE_TAG constant for worker tagging - NoteEditorViewModel.triggerOnSaveSync(): Tag SyncWorker with "onsave" tag - SyncWorker.doWork(): Skip global cooldown check for onSave-tagged workers - onSave retains 3 protection layers: 5s own throttle, tryStartSync mutex, syncMutex - Auto/WiFi/periodic syncs still respect 30s global cooldown