In Conductor, and whenever AskUserQuestion fails, prose is the only channel,
and the prose fallback defined only the D<N> decision brief. Phase 2A/2B
diagnostic questions have no option set, so the model dropped the phase.
Office-hours' preamble now defines the Q<N> open-question form (question,
why I'm asking, what a strong answer sounds like) and routes free-text
replies to it; the diagnostic sections name it. Scoped to office-hours so
every other skill's preamble is unchanged. Ported from PR #2729.
Co-authored-by: Bharadwaj Mittapelli <bharadwajmittapelli@gmail.com>