[WooCommerce Subscriptions] Modify renewal intervals

wcs_custom_extend_period_intervals.php

/**
 * Extend subscription period intervals to include a 364th option
 * 
 * @param array $intervals Array of interval strings (e.g., [1 => 'every', 2 => 'every 2nd', ...])
 * @return array Modified intervals array with 364
 */
function wcs_custom_extend_period_intervals ( $intervals ) {
	// Keep the existing intervals (1-6)
	// Add interval 364
	$intervals[ 364 ] = sprintf( 
		_x( 'every %s', 'period interval with ordinal number (e.g. "every 2nd"', 'woocommerce-subscriptions' ), 
		wcs_append_numeral_suffix( 364 ) 
	);
	
	// Sort by key to maintain order (1, 2, 3, 4, 5, 6, 364)
	ksort( $intervals );
	
	return $intervals;
}
add_filter( 'woocommerce_subscription_period_interval_strings', 'wcs_custom_extend_period_intervals', 10, 1 );