feat: add frontend source (fix submodule), compact node design

- Remove nested .git from Vite scaffold
- Horizontal node layout: icon left, label+IP right, reduced height

frontend/src/lib/utils.ts

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