feat(onboarding): support TI_ONBOARDING_DEFAULT_SITE redirect

When the TI_ONBOARDING_DEFAULT_SITE constant is defined, the
post-activation redirect now lands on the preview/import screen for
that site (admin.php?page=neve-onboarding&site=<slug>) instead of the
default search/welcome screen. The onboarding store resolves the
?site=<slug> query param against the bootstrapped sites list (across
all builders) and starts at step 3 with currentSite preset; if the
slug is unknown the app falls back to the existing search screen.

This lets distributions and embedded environments (e.g. WordPress
Playground) deep-link a user straight to the import flow for a chosen
starter site.

Made-with: Cursor

Author: selul

includes/Admin.php

@@ -398,15 +398,16 @@ public function activation_redirect() {
 		}
 
 		delete_option( 'tpc_maybe_run_onboarding' );
-		wp_safe_redirect(
-			add_query_arg(
-				array(
-					'page' => 'neve-onboarding',
-					'show' => 'welcome',
-				),
-				admin_url( 'admin.php' )
-			)
-		);
+
+		$query_args = array( 'page' => 'neve-onboarding' );
+
+		if ( defined( 'TI_ONBOARDING_DEFAULT_SITE' ) && TI_ONBOARDING_DEFAULT_SITE ) {
+			$query_args['site'] = sanitize_key( TI_ONBOARDING_DEFAULT_SITE );
+		} else {
+			$query_args['show'] = 'welcome';
+		}
+
+		wp_safe_redirect( add_query_arg( $query_args, admin_url( 'admin.php' ) ) );
 		exit();
 	}
 

onboarding/src/store/reducer.js

@@ -16,15 +16,32 @@ const initialLicense = licenseTIOB || {
 	tier: 0,
 };
 
+const params = new URLSearchParams( window.location.search );
+const defaultSiteSlug = params.get( 'site' );
+
+const findSiteBySlug = ( slug ) => {
+	const builders = onboarding?.sites?.sites || {};
+	for ( const builder of Object.keys( builders ) ) {
+		if ( builders[ builder ]?.[ slug ] ) {
+			return builders[ builder ][ slug ];
+		}
+	}
+	return null;
+};
+
+const defaultSite = defaultSiteSlug ? findSiteBySlug( defaultSiteSlug ) : null;
+
 const initialState = {
 	sites: onboarding.sites || {},
 	editor: selectedEditor,
 	category: '',
-	currentSite: null,
+	currentSite: defaultSite,
 	fetching: false,
 	searchQuery: '',
 	license: initialLicense,
-	onboardingStep: window.location.search.includes('show=welcome') ? 1 : 2,
+	onboardingStep: defaultSite
+		? 3
+		: ( window.location.search.includes('show=welcome') ? 1 : 2 ),
 	userCustomSettings: {
 		siteName: null,
 		siteLogo: null,