Reverse charges and adjust family payment schedules

A few updates to billing.

• Reverse charges in bulk. Select charges or credits on a camper’s or family’s Activity and undo them with one Reverse selected action. The charge and its reversal fold into one line, tagged Reversed.
• Adjust a family’s whole schedule at once. Open Adjust payment schedule to resize every camper’s plan in one place. A camper who owes with nothing scheduled is flagged.
• See the statement the way a family does. Switch between the full admin view and the clean view parents see.
• Reminders now match invoices. They carry the same check, cash, or wire instructions, invoice PDF, and fee breakdown.
• Confirm before charging. Taking a payment asks you to confirm the amount first.
• Financial contact on statements. Statements now use a family’s financial contact email when one’s set.