chore: import upstream snapshot with attribution

sdk/javascript/scripts/smoke.mjs

@@ -0,0 +1,17 @@
+/**
+ * Packaging smoke test: load the BUILT dist/ through Node's real CJS and ESM
+ * loaders. Unit tests run under vitest's bundler-like resolver and cannot catch
+ * a dual-format misconfig (CJS parsed as ESM, or extensionless ESM specifiers),
+ * so this guards `npm publish` against shipping an unconsumable package.
+ * Run after `npm run build`.
+ */
+import { createRequire } from 'node:module';
+
+const require = createRequire(import.meta.url);
+const cjs = require('../dist/cjs/index.js');
+if (typeof cjs.OpenWAClient !== 'function') throw new Error('CJS: OpenWAClient missing');
+
+const esm = await import(new URL('../dist/esm/index.js', import.meta.url).href);
+if (typeof esm.OpenWAClient !== 'function') throw new Error('ESM: OpenWAClient missing');
+
+console.log('smoke OK: require() + import() both resolve OpenWAClient');