[Money] Teacher/Staff Payroll via Stripe + 1099 Prep

Raised Sept 25. Money currently only flows one direction (families pay in). Bigger programs need to pay teachers/staff out through the same Stripe infrastructure rather than handling payroll separately, and then produce 1099s for contractors at year end. Two-part scope: (1) pay teachers/contractors out via Stripe Connect, tracked per co-op; (2) generate 1099-NEC forms from those payouts at year end. Real infrastructure lift, this is a second money-movement direction on top of the existing family-to-co-op billing engine, not a small add-on.