fix(create-next-app): add missing metadata type (#52299)

This pull request adds the missing `Metadata` type declaration to the
root layout of the `create-next-app` templates. The metadata object was
missing its type definition, which has been resolved by adding the
appropriate type import and annotation.

---------

packages/create-next-app/templates/app-tw/ts/app/layout.tsx

@@ -1,9 +1,10 @@
 import './globals.css'
+import type { Metadata } from 'next'
 import { Inter } from 'next/font/google'
 
 const inter = Inter({ subsets: ['latin'] })
 
-export const metadata = {
+export const metadata: Metadata = {
   title: 'Create Next App',
   description: 'Generated by create next app',
 }

packages/create-next-app/templates/app/ts/app/layout.tsx

@@ -1,9 +1,10 @@
 import './globals.css'
+import type { Metadata } from 'next'
 import { Inter } from 'next/font/google'
 
 const inter = Inter({ subsets: ['latin'] })
 
-export const metadata = {
+export const metadata: Metadata = {
   title: 'Create Next App',
   description: 'Generated by create next app',
 }