nwc: fix pay_invoice reply reliability, rate-limit drops, always reply

Port of master 8cb18821 (refs #80), adapted to staging's nwc event loop.

(a) pay_invoice: sendLightning runs xpay to completion and finalize() sets
p.ref = preimage, so return that directly instead of polling listpays and
racing a 20s timeout that returned a misleading "Payment timed out" even
when the payment settled. Keep a longer listpays loop as a fallback; on
still-in-flight return an explicit "check with lookup_invoice".

(b) rate limiting: raised per-pubkey cap 5 -> 60/min, and over-limit
requests now get a NIP-47 RATE_LIMITED reply instead of a silent drop that
looked like a lost reply. Every request path now always sends a 23195
reply (success, error, or handler-returned-nothing) so a client never
hangs. Pulled the reply/encrypt logic into a reply() helper.

The notify default-on part of 8cb18821 is intentionally NOT ported: master
10284aa1 reverted it to opt-in, which is already staging's behavior
(notify = String(notify) === "true").

Co-Authored-By: Claude Opus 4.8 <[email protected]>

0 files changed, 0 insertions, 0 deletions