Build a REST and SSE Event UI with an AI Chat Component

In Next.js, implement REST endpoints and a Server-Sent Events stream, display streamed events in a UI, and add an AI chat component. Describe how you would use an AI coding assistant while retaining responsibility for the specification and correctness. ### Constraints and Clarifying Questions The event schema, persistence, authentication, chat provider, and reconnect policy are not specified. Define a small explicit contract before implementation. Prioritize a functioning REST-to-event-stream path and then the chat component. The chat must have a real request, response, failure, and completion model; a visual input alone is not a completed design. ### What a Strong Answer Covers Endpoint responsibilities, SSE framing, client subscription lifecycle, reconnection and duplicate handling, REST mutation behavior, chat request state, cancellation, and a bounded AI-assisted implementation workflow. ### Follow-up Questions - What happens when the browser reconnects after missing events? - Why should creating an event use a mutation endpoint rather than the SSE subscription itself? - How would you prevent a failed chat request from looking like a completed answer?