Features phase 2: gift/swap/ark primitives leave the core wallet

wallet.js drops from 2,762 to 2,374 lines and now exposes two generic
seams instead of feature code:
- registerCoinLock()/lockedCoinIds(): features contribute coin ids that
  spending and the balance treat as unavailable (gift reservations).
- loadFeatureState()/saveFeatureState(): namespaced per-wallet persisted
  state.

src/features/gifts-wallet.js takes the whole gift engine — reservation
sets, gift records, coin selection, the SIGHASH_SINGLE/NONE PSBT
builder, the compact codec, claim building, nostr-locked gifts — as an
installGiftWallet(wallet) instance install plus standalone exports.
Swap storage/key helpers (loadSwaps/saveSwaps/swapNode/nextSwapIndex)
install from swap.js; ark state storage installs from the ark feature.
The silent-payment scan worker only embeds when the sp feature ships
(wallet.js already tolerated its absence).

Minimal profile: 412KB, down from 476KB (full: 578KB). All suites pass:
ark UI e2e, ArkManager crash-resume, gift lifecycle, minimal smoke.

SP's engine (scanning, BIP-352 signing) stays in wallet.js — extracting
it safely wants an SP e2e harness on this stack first.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01QFAcD4V284DvYZZHP7Rxxy

1 files changed, 5 insertions, 2 deletions

diff --git a/build.js b/build.js
index 8a0805b..a40a949 100644
--- a/build.js
+++ b/build.js
@@ -177,7 +177,10 @@ export async function buildHtml({ minify = true, pwa = minify, features = proces
   let js = await result.outputs[0].text();
   // Guard against a literal </script> inside the bundle closing our tag early.
   js = js.replaceAll('</script', '<\\/script');
-  const workerB64 = Buffer.from(await buildSpWorker({ minify })).toString('base64');
+  // The silent-payment scan worker only ships when the sp feature does.
+  const workerB64 = enabledFeatures(features).includes('sp')
+    ? Buffer.from(await buildSpWorker({ minify })).toString('base64')
+    : '';
   const css = await Bun.file('./src/style.css').text();
 
   return `<!doctype html>
@@ -193,7 +196,7 @@ ${pwa ? PWA_HEAD : ''}<style>${css}</style>
 </head>
 <body>
 <div id="app"></div>
-<script>globalThis.__SP_WORKER__=${JSON.stringify(workerB64)}</script>
+${workerB64 ? `<script>globalThis.__SP_WORKER__=${JSON.stringify(workerB64)}</script>` : ''}
 <script>${js}</script>
 ${pwa ? SW_REGISTER + '\n' : ''}</body>
 </html>`;