Reduce dense-roster participant and attendance render time

Stress Eclipse with 24 councillors and 48 deputy roles showed approximate development render timings of 15.3s for Oppmøteoversikt, 6.3s compensation, 5.6s absences, and 4.0s Møtedeltakere. Profile query counts and repeated canonical replacement-candidate/role lookups, batch shared-person state, and set practical performance budgets for six-list dense rosters. Preserve exact eligibility and authorization semantics.