sattle: Quasar PWA scaffold with lnurlcash-kit protocol core

M1: Quasar 2 / Vue 3 / TS / Pinia / i18n / PWA app shell in the lnurl-wallet
palette (#002222/#004444/#55ffcc, Noto Sans). Protocol layer is the external
lnurlcash-kit library (git dependency on the fork until upstream merges the
prepare fix / publishes to npm); keys.ts + receive.ts vendored from
lnurl-wallet with the derivation domain renamed to 'sattle'. Nix dev shell,
ci workflow (typecheck, vitest, pwa build).

src-pwa/register-sw.ts

@@ -0,0 +1,41 @@
+import { register } from "register-service-worker";
+
+// The ready(), registered(), cached(), updatefound() and updated()
+// events passes a ServiceWorkerRegistration instance in their arguments.
+// ServiceWorkerRegistration: https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorkerRegistration
+
+register(import.meta.env.QUASAR_SERVICE_WORKER_FILE, {
+  // The registrationOptions object will be passed as the second argument
+  // to ServiceWorkerContainer.register()
+  // https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorkerContainer/register#Parameter
+
+  // registrationOptions: { scope: './' },
+
+  ready(/* registration */) {
+    // console.log('Service worker is active.')
+  },
+
+  registered(/* registration */) {
+    // console.log('Service worker has been registered.')
+  },
+
+  cached(/* registration */) {
+    // console.log('Content has been cached for offline use.')
+  },
+
+  updatefound(/* registration */) {
+    // console.log('New content is downloading.')
+  },
+
+  updated(/* registration */) {
+    // console.log('New content is available; please refresh.')
+  },
+
+  offline() {
+    // console.log('No internet connection found. App is running in offline mode.')
+  },
+
+  error(/* err */) {
+    // console.error('Error during service worker registration:', err)
+  }
+});