Add Ark <-> Lightning via the ASP (captaind-native submarine swaps)

The ASP is the HTLC counterparty (second.tech's protocol), so no external
swap provider is needed: paying a bolt11 converts pubkey vtxos into
ServerHtlcSend vtxos the server can only claim by revealing the invoice
preimage; receiving grants ServerHtlcRecv vtxos claimed by revealing ours.
Failure paths cosign the HTLC back (revocation) — proven end-to-end against
regtest captaind, which independently derives the HTLC taproots.

- ark/lightning.js: bolt11 decode, lightning fee schedules, all pay/receive
  gRPC-web wrappers (cosign, initiate, status, revocation, hold-invoice
  receive flow, anti-DoS attestation)
- ark/send.js: arkoor builder generalized to policy outputs (pubkey /
  serverHtlcSend / serverHtlcRecv), two-leaf taproot trees, HTLC clause
  scripts, reusable per-part cosign helpers for package RPCs
- ark/manager.js: ln-pay and ln-recv crash-safe action state machines
  (deterministic receive preimages from the seed, chain 5), mailbox
  lightning notifications, unpayable-invoice -> instant revocation
- proto.js: lightning ArkInfo fields + mailbox lightning message decode
- validate/refresh: policy-aware vtxo validation and reconstruction
- features: bolt11 routes via ark when the balance covers it (Boltz stays
  the fallback), lightning-invoice receive on the Ark pane
- tools/ark/ln-test.js: harness proving HTLC cosign + revocation against
  captaind; manager-test.js updated for the consolidated bc-container chain

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

1 files changed, 8 insertions, 1 deletions

diff --git a/src/features/swaps.js b/src/features/swaps.js
index 091ca32..bad823c 100644
--- a/src/features/swaps.js
+++ b/src/features/swaps.js
@@ -132,7 +132,11 @@ export function swapsFeature(ctx) {
       line(t('status'), swap.status === 'claimed' ? 'Settled ✓' : swap.status));
   }
 
-  async function startLnSend(invoice, meta = null) {
+  async function startLnSend(invoice, meta = null, skipArk = false) {
+    // The ark feature pays bolt11 straight from the ark balance when it can
+    // cover it (the ASP is the swap counterparty) — cheaper and instant, so
+    // it gets first refusal before the on-chain Boltz submarine path.
+    if (!skipArk && ctx.hook('startArkLnPay', invoice, meta)) return;
     ui.sendError = ''; ui.lnSend = null; ui.lnSent = null; ui.lnPayMeta = meta; ui.lnSendBusy = true; render();
     try { ui.lnSend = await swaps.quoteSubmarine(invoice); }
     catch (e) { ui.sendError = e.message; }
@@ -228,5 +232,8 @@ export function swapsFeature(ctx) {
     // the review as a zap (recipient name, comment). Returns true so the hook
     // dispatcher stops here.
     startLnPay(invoice, meta) { startLnSend(invoice, meta || null); return true; },
+    // The ark feature falls back here when the ark balance can't cover an
+    // invoice after fees — skipArk avoids bouncing back and forth.
+    startLnPayBoltz(invoice, meta) { startLnSend(invoice, meta || null, true); return true; },
   };
 }