Grin as a new asset arm in the tips machinery (no grin-lws change, no custodial
grin_transactions/grin_outputs port):
- GrinClient::get_outputs([commit]) (funding: present+height=confirmed) +
get_kernel(excess) (sweep spend-height); reached via state.chains.grin.
- create-gating (supported_tip_asset grin, validate 66-hex commitment,
confirmations_for_asset grin=10), grin_commitment column (migration).
- confirmation worker grin arm: get_outputs present -> confs; amount AUTO-VERIFY
with warn (voucher hides amount; not a theft vector; matches legacy).
- sweep reconciler grin arm: get_outputs-absent + get_kernel height at depth 10 ->
settle; absence-without-kernel -> no settle (recoverable, never missettle);
reorg revert only on commitment reappearing; probe error never settles/reverts.
- 5 grin tests + pure-helper unit tests; 251 lib + 24 tips green.
Amount-verification note: the voucher's bulletproof rewind nonce is random +
untransmitted, so it can't be rewound today; a clean non-custodial fast-follow is
to have the client send the per-voucher rewind nonce and verify via rangeproof
rewind (nonce reveals amount only, not spend authority).
jwinterm