Hey bro, thank you for the question. I tried to get by without covering that because I'm not using app router 😂. Here's the answer from one of the good guys on Reddit:
Add:
export const metadata = {
other: {
google-site-verification: "ewawsLX9_9TZyMFjdeqxxGSWXpYSk6vUaAgtwwqakFE"
}};
to your root layout (app/layout.tsx) or home page (app/page.tsx). Both are going to do the same thing on the home page, they will create:
<head>
<meta name="google-site-verification" content="ewawsLX9_9TZyMFjdeqxxGSWXpYSk6vUaAgtwwqakFE"/>
</head>