Add a dev menu item to show the home screen

apps/yaak-client/routes/index.tsx

@@ -1,10 +1,19 @@
 import { createFileRoute } from "@tanstack/react-router";
+import { Onboarding } from "../components/Onboarding";
 import { RedirectToLatestWorkspace } from "../components/RedirectToLatestWorkspace";
 
+type IndexSearchSchema = {
+  /** Show the home screen even when workspaces exist. Set by the dev menu. */
+  home?: true;
+};
+
 export const Route = createFileRoute("/")({
   component: RouteComponent,
+  validateSearch: (search: Record<string, unknown>): IndexSearchSchema =>
+    search.home === true ? { home: true } : {},
 });
 
 function RouteComponent() {
-  return <RedirectToLatestWorkspace />;
+  const { home } = Route.useSearch();
+  return home ? <Onboarding /> : <RedirectToLatestWorkspace />;
 }