Bug Report: GitHub Mode Setup Next.js - You provided a `value` prop to a form field without an `onChange` handler.

[stuartmitchelhill]

Following a fresh install of Keystatic using Next.js with the quickstart command npm create @keystatic@latest and setting up GitHub mode using the guide found here results in an error on initial setup.

When visiting /keystatic for the first time after setup and updating keystatic.config for GitHub mode throws the following errors when attempting to input the "Deployed App URL"

1. Console error: You provided a value prop to a form field without an onChange handler. This will render a read-only field. If the field should be mutable use defaultValue. Otherwise, set either onChange or readOnly.

2. Runtime error: URL constructor: h is not a valid URL.