Function join_with_device_pairing 

pub async fn join_with_device_pairing(
    pairing: &PreparedDevicePairing,
    layout: StoreLayout,
    synced_tables: Vec<SyncedTable>,
    migrations: Vec<Migration>,
    coven_migration_policy: CovenMigrationPolicy,
    exact_upload_verification: ExactUploadVerification,
    transfer_limits: TransferLimits,
    key_custody: KeyCustody,
    identity_custody: IdentityCustody,
    oauth_clients: OAuthClients,
    oauth_tokens: Option<OAuthTokens>,
    cloudkit_ops: Option<Arc<dyn CloudKitOps>>,
    clock: ClockRef,
    on_progress: JoiningDeviceJoinProgressObserver,
    cancel: &Receiver<bool>,
) -> Result<DeviceJoinTransportOutcome, BootstrapError>

Complete the joining side after scanning the existing device’s one pairing code. The local session returns the invitation sealed to this attempt; the existing Store transport then performs registration and bootstrap. The caller’s Coven migration policy controls every writer open during bootstrap.