chore: Add frontend lock file and utils

- Add package-lock.json for reproducible builds
- Add lib/utils.ts with cn() helper
- Fix .gitignore to not exclude frontend/lib

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitignore

@@ -15,8 +15,11 @@ dist/
 downloads/
 eggs/
 .eggs/
-lib/
+# Python lib directories (not frontend/lib)
-lib64/
+/lib/
+/lib64/
+backend/lib/
+backend/lib64/
 parts/
 sdist/
 var/

frontend/lib/utils.ts

@@ -0,0 +1,6 @@
+import { type ClassValue, clsx } from "clsx";
+import { twMerge } from "tailwind-merge";
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs));
+}