Sending files to a remote server is never something that should need to be disabled, this must be an opt-in or it's time for a fork.

It is opt in. You have to manually sign in to Zed and enable the feature.

Agreed. The predict edit feature needs to be actively enabled before it'll do anything. And once it's enabled, it won't send up your private keys or environment variables. If their filename matches a glob in this list, or a list you configure.