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).

.vscode/settings.json

@@ -0,0 +1,14 @@
+{
+  "editor.bracketPairColorization.enabled": true,
+  "editor.guides.bracketPairs": true,
+  "editor.formatOnSave": true,
+  "editor.defaultFormatter": "esbenp.prettier-vscode",
+  "editor.codeActionsOnSave": ["source.fixAll.eslint"],
+  "eslint.validate": ["javascript", "javascriptreact", "typescript", "vue"],
+  "js/ts.tsdk.path": "node_modules/typescript/lib",
+  "search.exclude": {
+    "dist/": true,
+    ".quasar/": true,
+    "/quasar.config.js.temporary.*": true
+  }
+}