feat(paypal): guided setup wizard for manual credentials + OAuth flag gate

assets/js/paypal-setup-wizard.js

@@ -0,0 +1,70 @@
+// PayPal setup wizard — test connection step.
+//
+// Pings the wu_paypal_setup_wizard_test AJAX endpoint and renders the
+// status with Vue. Triggered from views/wizards/paypal-setup/test.php.
+//
+// @since 2.6.0
+
+(function($) {
+	$( document ).ready( function () {
+		if ( typeof wu_paypal_setup_wizard === 'undefined' ) {
+			return;
+		}
+
+		var data = wu_paypal_setup_wizard;
+
+		new Vue( {
+			el: '#wu-paypal-setup-wizard-test',
+			data: {
+				loading: true,
+				success: false,
+				webhookStatus: 'not_attempted',
+				errorMessage: data.error_message,
+				rawResponse: data.waiting_message,
+			},
+			mounted: function () {
+				this.runTest();
+			},
+			methods: {
+				runTest: function () {
+					var that = this;
+					this.loading = true;
+					this.success = false;
+					this.rawResponse = data.waiting_message;
+
+					$.ajax( {
+						url: data.ajax_url,
+						method: 'POST',
+						data: {
+							action: 'wu_paypal_setup_wizard_test',
+							nonce: data.nonce,
+							sandbox_mode: data.sandbox_mode,
+						},
+						success: function ( response ) {
+							that.loading = false;
+							that.rawResponse = JSON.stringify( response, null, 2 );
+
+							if ( response.success ) {
+								that.success = true;
+								that.webhookStatus = response.data.webhook_status || 'not_attempted';
+							} else {
+								that.success = false;
+								that.errorMessage =
+									( response.data && response.data.message ) ||
+									data.error_message;
+							}
+						},
+						error: function ( xhr ) {
+							that.loading = false;
+							that.success = false;
+							that.errorMessage = data.error_message;
+							that.rawResponse =
+								( xhr.responseText && xhr.responseText.slice( 0, 1000 ) ) ||
+								data.error_message;
+						},
+					} );
+				},
+			},
+		} );
+	} );
+} )( jQuery );

constants.php

@@ -51,3 +51,23 @@
 if ( ! defined('WU_EXTERNAL_CRON_ENABLED')) {
 	define('WU_EXTERNAL_CRON_ENABLED', false);
 }
+
+/**
+ * Feature flag: Enable PayPal OAuth ("Connect with PayPal") onboarding.
+ *
+ * When set to true, enables the PayPal Partner Referrals one-click onboarding
+ * flow. This requires an active PayPal Commerce Platform partner agreement —
+ * `/v2/customer/partner-referrals`, partner-token minting via the proxy, and
+ * `PayPal-Auth-Assertion` impersonation only work for approved partners.
+ *
+ * Defaults to false. Without partner status, merchants set up PayPal via the
+ * guided manual-credentials wizard (developer.paypal.com REST app). When
+ * Ultimate Multisite is approved as a PayPal partner again, define
+ * WU_PAYPAL_OAUTH_ENABLED as true in wp-config.php to re-enable the
+ * one-click flow.
+ *
+ * @since 2.6.0
+ */
+if ( ! defined('WU_PAYPAL_OAUTH_ENABLED')) {
+	define('WU_PAYPAL_OAUTH_ENABLED', false);
+}