Multisig deploy: quote the fee and address beside the threshold #465

The multisig deploy wizard keeps a two-press flow: choose threshold and deployment signer, press "Check fee and address" (relabelled in 4800374), then "Deploy multisig".

An attempt to quote on arrival — the way single-signer deploy works since b4f3819 — was reverted: the approval stage is where the threshold and signer are chosen, so an arrival-time quote priced the 1-of-N default nobody wanted and then advanced the stage past the fields (caught by the Create · approval UI Lab checkpoint).

The version that would work is a merged stage: the quote renders beside the threshold and signer picker, re-quotes (debounced) when either changes, and the button always reads "Deploy multisig". That is a redesign of the deployment stage machine (multisig-deploy-ui.ts — note: the file sits exactly at the 500-line cap), not a copy change, so it was left out of the copy-review branch.