Prepare the activation of a multisig wallet

Once the wallet is backed up (a passkey holds D and the kit is confirmed) and its address holds at least 101 TRX (activation_min_sun), builds the AccountPermissionUpdate that installs owner = 2-of-3 and active = 2-of-3 (transfers and contract calls only) over V, D and R, from a reference block, and returns its raw bytes. The network burns a 100 TRX fee when it lands. The device decodes and checks the raw itself, then signs it with D (the account's sole owner until then) and calls activation/complete. 409 when already active or not funded.