Add NIP-57 Lightning zaps (npub / lightning address / lnurl)

Send a Lightning zap to a nostr npub, a lightning address (name@domain),
or an lnurl. New src/lnurl.js does the resolution half — target → LNURL-pay
params → signed kind-9734 zap request → callback → bolt11 — and the new
zaps feature (src/features/zaps.js) drives the amount/comment UI, then hands
the invoice to the existing Boltz submarine-swap flow via a new
swaps.startLnPay hook, so there's one tested pay/review/confirm/success path.

Routing: a bolt11 is still caught by swaps; an npub still prefers an instant
free Ark zap when Ark can serve it, and only falls through to a Lightning
zap otherwise — ark's "no Ark address" screen also offers an explicit
"Zap over Lightning" fallback (gated on the zaps feature's canLnZap). A real
zap receipt is attributed only when the server advertises allowsNostr and we
know the recipient's pubkey; otherwise it degrades to a plain LNURL-pay.

Nostr seam gains nostrSign (finalize without publishing), nostrProfile
(kind-0 with lud16/lud06), and nostrRelays. Lightning addresses are
debounced in matchSendText since their regex matches mid-typing.

Verified: unit tests for parse/encode/zap-request; a live resolve→signed
9734→payable mainnet bolt11 against coinos; and an in-browser DOM smoke
(zap form + LNURL params over CORS + allowsNostr hint + handoff).

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

1 files changed, 5 insertions, 2 deletions

diff --git a/src/features/index.js b/src/features/index.js
index e63e816..e52b172 100644
--- a/src/features/index.js
+++ b/src/features/index.js
@@ -7,11 +7,14 @@
 import { giftsFeature } from './gifts.js';
 import { swapsFeature } from './swaps.js';
 import { arkFeature } from './ark.js';
+import { zapsFeature } from './zaps.js';
 import { spFeature } from './sp.js';
 import { syncFeature } from './sync.js';
 
 // NB order is meaningful where hooks stack: gifts' receive takeover and
-// balance line come before ark's, matching the pre-plugin layout.
+// balance line come before ark's, matching the pre-plugin layout. zaps sits
+// after ark so an npub prefers an instant Ark zap and only falls through to a
+// Lightning zap when Ark can't serve it.
 export function buildFeatures(ctx) {
-  return [giftsFeature(ctx), swapsFeature(ctx), arkFeature(ctx), spFeature(ctx), syncFeature(ctx)];
+  return [giftsFeature(ctx), swapsFeature(ctx), arkFeature(ctx), zapsFeature(ctx), spFeature(ctx), syncFeature(ctx)];
 }