[Bug]: Route [filament.{panel-id}.mails.preview] not defined on v4.x

[m-ristau]

What happened?

On v4.x, the mail preview throws the following error:
Route [filament.{panel-id}.mails.preview] not defined.

How to reproduce the bug

PR #72 fixed this for the main branch (v3.x) by auto-registering routes inside MailsPlugin::register(), but the fix has not been carried over to the v4.x branch yet.

Package Version

4.0.8

PHP Version

8.4.20

Laravel Version

12.56.0

Which operating systems does with happen with?

Linux

Notes

Until this is fixed, add the following to your PanelProvider manually:

use Backstage\Mails\Mails;

public function panel(Panel $panel): Panel
{
    return $panel
        ->plugin(MailsPlugin::make())
        ->routes(fn () => Mails::routes()); // add this
}