fix(export): preserve pitch for fallback speed audio

scripts/smoke-electron-main-cjs.mjs

@@ -0,0 +1,28 @@
+import fs from "node:fs/promises";
+
+const mainBundleUrl = new URL("../dist-electron/main.cjs", import.meta.url);
+const mainBundlePath = mainBundleUrl.pathname;
+
+let source;
+try {
+	source = await fs.readFile(mainBundleUrl, "utf8");
+} catch (error) {
+	throw new Error(`Unable to read dist-electron/main.cjs: ${error}`);
+}
+
+const esmImportPattern = /^[ \t]*import\s+(?:(?:[\w*{][^\n;]*?)\s+from\s+)?["'][^"']+["'];?/gm;
+const matches = [...source.matchAll(esmImportPattern)].map((match) => ({
+	line: source.slice(0, match.index).split(/\r?\n/).length,
+	text: match[0].trim(),
+}));
+
+if (matches.length > 0) {
+	const details = matches.map((match) => `line ${match.line}: ${match.text}`).join("\n");
+	throw new Error(`dist-electron/main.cjs contains ESM import syntax:\n${details}`);
+}
+
+if (/\bimport\.meta\b/.test(source)) {
+	throw new Error("dist-electron/main.cjs contains import.meta syntax");
+}
+
+console.log(`Electron main CJS smoke passed: ${mainBundlePath}`);