Add theme integration and shadcn setup in internal_frontend

internal_frontend/components/theme-provider.tsx

@@ -0,0 +1,11 @@
+"use client"
+
+import * as React from "react"
+import {ThemeProvider as NextThemesProvider} from "next-themes"
+
+export function ThemeProvider({
+                                  children,
+                                  ...props
+                              }: Readonly<React.ComponentProps<typeof NextThemesProvider>>) {
+    return <NextThemesProvider {...props}>{children}</NextThemesProvider>
+}