School reports redesigned; wallet reserve checked before every payout

The school reports view was rebuilt as a year-aware accordion, grouping sessions by school grade and academic year. School grade is now shown in the report header instead of the internal TSK level identifier.

The rewards system now checks the bolt wallet reserve before initiating any payout — monthly reports, special payouts, and direct sends all go through the same reserve check. If the reserve is insufficient, the system generates a top-up Lightning invoice for the shortfall rather than blocking the payout entirely.