perf(bundle): drop js-base64

lib/base64.ts

@@ -0,0 +1,14 @@
+export const encode = (s: string) => {
+  const bytes = new TextEncoder().encode(s);
+  return btoa(String.fromCharCode(...bytes));
+};
+
+export const decode = (base64: string) => {
+  try {
+    const binString = atob(base64);
+    const bytes = Uint8Array.from(binString, c => c.charCodeAt(0));
+    return new TextDecoder().decode(bytes);
+  } catch {
+    return undefined;
+  }
+};