Correct case attribution in compensation participation history

Stress Eclipse introduced Deputy 12 only as Councillor 14’s case-scoped bias replacement in STRESS-E-2. The compensation report incorrectly states Deputy 12 participated in 2/3 cases, STRESS-E-1 and STRESS-E-2. Derive per-case participation from canonical effective intervals and case-scoped overlays so a deputy is not backdated into earlier cases. Add mixed meeting-wide and case-only replacement coverage.