Retrieves the timezone of the site as a string.

Uses the `timezone_string` option to get a proper timezone name if available,
otherwise falls back to a manual UTC ± offset.

Example return values:

– ‘Europe/Rome’
– ‘America/North_Dakota/New_Salem’
– ‘UTC’
– ‘-06:30’
– ‘+00:00’
– ‘+08:45’

function wp_timezone_string() {
	$timezone_string = get_option( 'timezone_string' );

	if ( $timezone_string ) {
		return $timezone_string;
	}

	$offset  = (float) get_option( 'gmt_offset' );
	$hours   = (int) $offset;
	$minutes = ( $offset - $hours );

	$sign      = ( $offset