feat: refactor onboarding into a multi-step flow with dedicated routes and session state management

apps/frontend/src/routes/onboard.tsx

@@ -1,6 +1,5 @@
-import { OnboardPage } from '@/features/onboard/onboard-page';
-import { createFileRoute } from '@tanstack/react-router';
+import { Outlet, createFileRoute } from '@tanstack/react-router';
 
 export const Route = createFileRoute('/onboard')({
-  component: OnboardPage,
+  component: Outlet,
 });

apps/frontend/src/routes/onboard/complete.tsx

@@ -0,0 +1,6 @@
+import { OnboardCompletePage } from '@/features/onboard/onboard-complete-page';
+import { createFileRoute } from '@tanstack/react-router';
+
+export const Route = createFileRoute('/onboard/complete')({
+  component: OnboardCompletePage,
+});

apps/frontend/src/routes/onboard/index.tsx

@@ -0,0 +1,6 @@
+import { OnboardStartPage } from '@/features/onboard/onboard-start-page';
+import { createFileRoute } from '@tanstack/react-router';
+
+export const Route = createFileRoute('/onboard/')({
+  component: OnboardStartPage,
+});

apps/frontend/src/routes/onboard/verify.tsx

@@ -0,0 +1,6 @@
+import { OnboardVerifyPage } from '@/features/onboard/onboard-verify-page';
+import { createFileRoute } from '@tanstack/react-router';
+
+export const Route = createFileRoute('/onboard/verify')({
+  component: OnboardVerifyPage,
+});