/signup: stable account-creation door (redirects to register-mode onboarding)

apps/web/src/app/signup/page.tsx

@@ -0,0 +1,10 @@
+import { redirect } from "next/navigation";
+
+/**
+ * /signup — the account-creation door (linked from the chat client welcome and
+ * the participation manual). The onboarding page already opens in register
+ * mode; this route is the stable, speakable URL for it.
+ */
+export default function SignupRedirect(): React.ReactElement {
+  redirect("/onboarding");
+}