Send a message (SSE)

The response is a text/event-stream. OpenAPI cannot describe the event framing:

• event: message_start — data is a ChatMessageStartEvent. Lala started a message.
• event: chunk — data is a ChatChunkEvent. One text delta. Repeats.
• event: message_end — data is a ChatMessageEndEvent. That message is complete.
• event: restart — data is a ChatRestartEvent. Discard everything streamed so far.
• event: tool — data is a ChatToolEvent. Lala started or finished a tool. Use it to say what Lala is doing while it works. Purely cosmetic: a client may ignore it.
• event: sync — data is a ChatSyncEvent. A tool wrote data the app shows. Reload those screens. Repeats per resource, and done carries the whole set again.
• event: done — data is a ChatDoneEvent. The persisted messages and the reactions. Terminal.
• event: error — data is a ChatErrorEvent. Terminal. The status stays 200.

A turn can write to the planner, the deneme history and the profile through tools. The sync events say which of those changed, as soon as each write lands — refresh them then rather than waiting for done, so the planner is current when the student switches to it. done.changed repeats the set for a client that missed an event.

Lala answers in one message most of the time and in several when it writes the way a person texts. Render each message_start as a new bubble. The messages have no ids until done, which carries the persisted ChatMessage for each one.

The stream emits exactly one terminal event: done or error. A model failure is an error event, not an HTTP status. The 4xx responses below occur before the stream only.