Adds a server-side cash-in RPC so the ATM no longer supplies the withdraw
amount, fee, or attribution. The ATM sends a bunker-signed kind-21000
`create_withdraw` with just the gross `principal_sats` (the hardware-
attested fiat value); the handler derives everything else SERVER-SIDE:
- attribution = the VERIFIED transport `sender_pubkey` (never read from the
body), matched to an active machine on the authenticated wallet;
- fee = round(principal × super_cash_in) + round(principal × operator_cash_in),
per-leg rounding so it matches parse_settlement exactly (fee_mismatch=0);
- net = principal − fee → the withdraw amount the customer receives;
- stamps `extra={source:bitspire, type:cash_in, principal_sats, fee_sats,
nostr_sender_pubkey:<verified>, nostr_event_id}` onto the link.
The customer claims the NET link; the payout carries the stamped extra
(aiolabs/withdraw#3) and `_handle_payment` records the cash_in settlement
(spirekeeper#30) with cryptographic attribution — closing the vector where
`lnurlw_create_link` let the ATM set amount/fee/attribution freely.
Registered via `register_rpc("create_withdraw", …, AUTH_WALLET)` (extensions
register RPCs directly — withdraw already does). Soft-fails on lnbits without
`register_rpc`. Per-tx cap reads `super_config.max_cash_in_sats` defensively
(getattr) — the config field/UI is a fast-follow.
Wire schema pinned in #31. Depends on #30 (consumer-side settlement fix).
ci.yml / Merge pull request 'fix(settlements): process cash-in (outbound) payments, not just cash-out' (#30) from fix/cash-in-settlement into main (push) Failing after 0s
