Add setting to allow access to registration page for non-logged-in users

[jeffpaul]

Is your enhancement related to a problem? Please describe.

Currently, when Restricted Site Access is enabled, all front-end pages including the user registration page are restricted based on the plugin’s access rules. This prevents new users from registering when the site is under restriction.

To improve flexibility, introduce a new setting (default: disabled) that allows administrators to permit access to the registration page (/wp-login.php?action=register or a custom registration URL) for any user who is not logged in.

Designs

Potential code snippet from @dkotter to consider:

add_filter(
	'restricted_site_access_is_restricted',
	function ( $is_restricted, $wp ) {
		if ( ! empty( $wp->request ) && 'wp-signup.php' === $wp->request ) {
			$is_restricted = false;
		}
		return $is_restricted;
	},
	10,
	2
);

Describe alternatives you've considered

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[sanketio]

On single site the registration page isn't restricted — RSA only hooks parse_request and wp-login.php never runs it; I registered a user on a fully restricted site to confirm.

On multisite, wp-login.php?action=register redirects to wp-signup.php, which requires wp-blog-header.php before its is_multisite() bail, so parse_request fires and RSA blocks it there.

That narrows the setting to unblocking wp-signup.php; matching wp_signup_location rather than a literal path would keep it correct if signup is relocated.