/rank's Step 2 scoring agents already return strengths and gaps per job,
but Step 4 only persisted rank_score/rank_verdict/rank_date - both arrays
were printed once in Step 5 and then discarded. Store them verbatim in
seen_jobs.json (replaced, not accumulated, on --all re-ranks) so downstream
consumers can read real triage findings instead of re-deriving them.
Discussed in #258.
