Conversation history persists across page refreshes

The Vercel AI SDK's useChat hook stores messages exclusively in React component state — a page refresh destroys the entire conversation with no recovery path. For any application where users build on prior context (debugging sessions, multi-step workflows, ongoing support threads), this is a reliability failure under iso-25010:2011: the system cannot maintain its service when subjected to a routine browser event. Users who lose history mid-workflow may lose irreplaceable problem context. Data-integrity also demands that committed user interactions not vanish silently; a conversation a user considers saved is, in effect, corrupted when it disappears.

Persist messages to localStorage on every state change and load them as initialMessages on mount in src/components/chat/ChatWindow.tsx.

const { messages } = useChat({
  initialMessages: JSON.parse(
    localStorage.getItem('chat-history') || '[]'
  ),
});

useEffect(() => {
  localStorage.setItem('chat-history', JSON.stringify(messages));
}, [messages]);

For authenticated users, replace localStorage with a database-backed route at app/api/chat/history/route.ts — write after each exchange and read on mount. localStorage is an acceptable fallback for anonymous sessions but must not be the only mechanism for logged-in users where history is a product guarantee.