Follow-up to the #48194 pick: it was written before #43665 landed and
re-added its own /send-poll sidecar route and poll import. Collapse the
duplicates:
- keep #43665's /send-poll route (>=2 trimmed string options) as the
single sidecar implementation; drop #48194's variant
- drop the duplicated poll import in the sidecar destructure
- make adapter.send_poll() a thin wrapper over _sidecar_send_poll(), the
one /send-poll client (shared with the poll-backed clarify path), and
align its validation to the sidecar's >=2-options contract
324f310263