feat: initial implementation of WooList phpList Integration plugin v1.0.0

- phpList REST API wrapper with subscriber get-or-create + list assignment
- WooCommerce Settings tab (5 sections: connection, orders, signup, newsletter)
- Test Connection button via admin-post action
- Hooks for order completed/cancelled and user_register events
- [woolist_newsletter] shortcode with jQuery AJAX, fixed & auto-generated coupons
- Responsive front-end form styles and JS with loading/success/error states

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

woolist-phplist/assets/js/woolist-public.js

@@ -0,0 +1,69 @@
+/* global woolist, jQuery */
+( function ( $ ) {
+	'use strict';
+
+	$( document ).on( 'submit', '#woolist-newsletter-form', function ( e ) {
+		e.preventDefault();
+
+		var $form    = $( this );
+		var $wrap    = $form.closest( '.woolist-newsletter-wrap' );
+		var $btn     = $form.find( '.woolist-submit-btn' );
+		var $email   = $form.find( '[name="woolist_email"]' );
+		var $resp    = $wrap.find( '.woolist-response' );
+
+		// Clear previous response state.
+		$resp.hide().removeClass( 'woolist-success woolist-error' ).html( '' );
+
+		var email = $email.val().trim();
+		if ( ! email ) {
+			showResponse( $resp, woolist.i18n.error, false );
+			return;
+		}
+
+		// Loading state.
+		var originalLabel = $btn.text();
+		$btn.prop( 'disabled', true ).text( woolist.i18n.subscribing );
+
+		$.ajax( {
+			url:    woolist.ajaxurl,
+			method: 'POST',
+			data:   {
+				action:        'woolist_newsletter_submit',
+				nonce:         woolist.nonce,
+				woolist_email: email,
+			},
+		} )
+		.done( function ( response ) {
+			if ( response.success && response.data && response.data.message ) {
+				// Hide the form, show the success message.
+				$form.slideUp( 200 );
+				showResponse( $resp, response.data.message, true );
+			} else {
+				var msg = ( response.data && response.data.message )
+					? response.data.message
+					: woolist.i18n.error;
+				showResponse( $resp, msg, false );
+				$btn.prop( 'disabled', false ).text( originalLabel );
+			}
+		} )
+		.fail( function () {
+			showResponse( $resp, woolist.i18n.error, false );
+			$btn.prop( 'disabled', false ).text( originalLabel );
+		} );
+	} );
+
+	/**
+	 * Display a response message in the response container.
+	 *
+	 * @param {jQuery} $el      The response element.
+	 * @param {string} message  HTML or text message to display.
+	 * @param {boolean} success Whether this is a success message.
+	 */
+	function showResponse( $el, message, success ) {
+		$el
+			.addClass( success ? 'woolist-success' : 'woolist-error' )
+			.html( message )
+			.slideDown( 200 );
+	}
+
+} )( jQuery );