Most wallets — Minibits, Nutstash, cdk-cli — default to reading cashuB
(V4) now, so that is what we send. cashuA stays as the fallback rather
than the default: it is still valid everywhere, so a token this wallet
cannot express in V4 (a multi-mint one) is worth sending in V3 rather
than failing the send outright. That path warns, because by the time
`send_token_at` serializes, the proofs are already marked spent.
The V4 encoder is the reference implementation's, not ours. The envelope
puts the keyset id and signature on the wire as raw CBOR bytes under
single-letter keys, and a token subtly wrong there is money the receiver
cannot redeem — so upstream owns the encoding, the way it already owns
keyset-id resolution. Our own hand-written decoder reads what upstream
writes in the new test, which is agreement between two independent
implementations rather than a round trip through one codec.
Two refusals are deliberate and tested: a multi-mint token has no V4
form, and a truncated v2 keyset id must never be baked into a token we
emit (the framework-pt case) — it is only resolvable against the mint's
keyset list.
Also folds SendBitcoinModal onto the shared PaymentSuccessPane it had a
private copy of, so on-chain, Lightning and ecash all show the same
screen and the copyable-identifier row is defined once.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
