Add Nostr Wallet Connect (NIP-47) — hal as a wallet service

Other apps can connect over nostr and pay from this wallet without touching
its keys, within a per-payment and daily budget the user sets, revocable at
any time. hal holds no native Lightning balance, so every operation runs over
Ark: pay_invoice takes the swap bridge when configured and falls back to the
ASP's lightning-send, make_invoice mints on the ASP. NWC availability
therefore tracks Ark availability.

- kinds 13194/23194/23195, nip44_v2 and nip04, replying in whichever scheme
  the request used; every request gets a reply so clients never hang
- each connection gets its own service keypair, so revoking one can't affect
  the others and none is tied to the user's nostr identity
- budgets are checked BEFORE spending, not reconciled after
- requests are ignored unless signed by that connection's client key, and
  replayed/stale events (>120s) can't re-trigger a payment
- Settings card to create, show (URI + QR) and revoke connections, and it
  says plainly that this only works while a tab is open

tools/nwc-test.js drives it as a real client: both encryption schemes, budget
refusal with a genuine over-limit invoice, unsupported-method errors, and a
request from an unauthorized key being ignored.

Co-Authored-By: Claude Fable 5 <[email protected]>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/features/index.js b/src/features/index.js
index e52b172..06d8d4d 100644
--- a/src/features/index.js
+++ b/src/features/index.js
@@ -10,11 +10,12 @@ import { arkFeature } from './ark.js';
 import { zapsFeature } from './zaps.js';
 import { spFeature } from './sp.js';
 import { syncFeature } from './sync.js';
+import { nwcFeature } from './nwc.js';
 
 // NB order is meaningful where hooks stack: gifts' receive takeover and
 // 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), zapsFeature(ctx), spFeature(ctx), syncFeature(ctx)];
+  return [giftsFeature(ctx), swapsFeature(ctx), arkFeature(ctx), zapsFeature(ctx), spFeature(ctx), nwcFeature(ctx), syncFeature(ctx)];
 }