Generate session titles using LLM

[PriyangaPKini]

Summary

Currently session titles are set to the raw first question text (truncated at 80 chars). Instead, use a lightweight LLM call to generate a concise, descriptive title from the first question + response.

Approach

• After the first ask() completes in wrapSession, fire a background LLM call (e.g. Haiku) with the question and response
• Generate a short title (5-10 words)
• Update the session title via updateSessionTitle
• Title appears in sidebar after a short delay (non-blocking)

Considerations

• Adds latency and cost per new session (mitigate with a cheap/fast model)
• Should be async/non-blocking so it doesn't delay the response
• Fallback to raw question text if the LLM call fails

Priority: Low