Vibe Chat

Main Vibe Search conversation endpoint. Returns either a follow-up question or search results.

Decomposition status (see also: helpers above this function): ✓ _strip_explicit_removals — pure transform ✓ _handle_cross_metro_response — early-return path ✓ _handle_unsupported_response — early-return path ✓ _dedup_already_shown — pure transform (more-intent dedup) ✓ _expand_to_similar_neighborhoods — async, Brief 2 §2.3 ✓ _run_search_with_expansion — orchestrates the search flow … _setup_chat_state — TODO (rate limits, parse, auth) … _build_zero_result_response — TODO (diagnostics + Claude reply) … _build_question_response — TODO (_chat_with_ai for follow-ups)

Each TODO would let us unit-test that step in isolation. Filed against the next time we touch this handler.