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, 21 insertions, 5 deletions

diff --git a/src/nostr.js b/src/nostr.js
index e73aa5d..407663c 100644
--- a/src/nostr.js
+++ b/src/nostr.js
@@ -61,7 +61,15 @@ export async function fetchNostrProfile(pubkeyHex, relays = PROFILE_RELAYS) {
   if (!best) return null;
   try {
     const m = JSON.parse(best.content);
-    return { name: m.display_name || m.name || null, picture: m.picture || null, nip05: m.nip05 || null };
+    return {
+      name: m.display_name || m.name || null,
+      picture: m.picture || null,
+      nip05: m.nip05 || null,
+      // NIP-57/LUD-16/06: where to send a Lightning zap. lud16 is a
+      // lightning address (name@domain); lud06 is a bech32 lnurl.
+      lud16: typeof m.lud16 === 'string' ? m.lud16.trim() : null,
+      lud06: typeof m.lud06 === 'string' ? m.lud06.trim() : null,
+    };
   } catch { return null; }
 }
 
@@ -188,14 +196,22 @@ export class NostrSync {
   // Used by features that speak their own event kinds (e.g. ark zaps).
   async publishEvent(partial) {
     if (!this.sk) return null;
-    let evt;
-    try {
-      evt = finalizeEvent({ created_at: Math.floor(Date.now() / 1000), tags: [], content: '', ...partial }, this.sk);
-    } catch { return null; }
+    const evt = this.signEvent(partial);
+    if (!evt) return null;
     await Promise.allSettled(pool.publish(this.relays, evt));
     return evt;
   }
 
+  // Sign an event with our key WITHOUT publishing it. A NIP-57 zap request
+  // (kind 9734) is signed by the sender but handed to the recipient's LNURL
+  // server — never broadcast to relays by us — so it needs signing alone.
+  signEvent(partial) {
+    if (!this.sk) return null;
+    try {
+      return finalizeEvent({ created_at: Math.floor(Date.now() / 1000), tags: [], content: '', ...partial }, this.sk);
+    } catch { return null; }
+  }
+
   // Fetch events matching a filter from the relays (best-effort).
   async fetchEvents(filter, maxWait = 5000) {
     try { return await pool.querySync(this.relays, filter, { maxWait }); } catch { return []; }