Add swimming pool seed with full grid system data

Seeds: discipline, facility (8 lanes), time brackets (5), pricing rules
(80 rules across all lanes × brackets × group sizes), 4 coaches,
4 programs, 6 training groups with weekly schedules, 20 players
enrolled across groups, training bookings for current week, hourly
bookings, and a maintenance blackout date.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>