BuiltInWallet.signMessage read `recovery` from libauth's recoverable
signature, but libauth v3 names it `recoveryId`. The flag byte came out as
0, so verifiers recovered the right key only when the true recovery id
happened to be 1. Signed DNS manifests and Studio uploads failed with
"signature does not match current on-chain NFT owner" and a different
derived address each attempt. Read the right field, fail loudly if it is
missing, rebuild the browser bundle and move every importer to the new
bundle URL. Also lands the registrar's signRecordsManifest that the bundle
already shipped.