Add Yoco processing fee tracking to payments, settings, and reports

Estimates and snapshots the Yoco card-processing fee (always church-borne)
on every card payment, lets the admin configure in-person/online fee % per
plan in Settings -> Payments, and surfaces the fee alongside gross revenue
across the Finance/Profit reports, Master Orders, Revenue Detailed, and the
full cashup reconciliation flow (close-out screen, Cashup report, and audit
trail) so payout figures match what actually lands in the bank.

backend/prisma/migrations/20260728060433_add_yoco_fee_fields_to_payment/migration.sql

@@ -0,0 +1,5 @@
+-- AlterTable
+ALTER TABLE "Payment" ADD COLUMN     "feeAmount" DOUBLE PRECISION,
+ADD COLUMN     "feeChannel" TEXT,
+ADD COLUMN     "feePayer" TEXT,
+ADD COLUMN     "feeRate" DOUBLE PRECISION;

backend/prisma/migrations/20260728065200_add_event_fee_payer_override/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Event" ADD COLUMN     "feePayerOnline" TEXT;

backend/prisma/migrations/20260728070306_remove_fee_payer_fields/migration.sql

@@ -0,0 +1,12 @@
+/*
+  Warnings:
+
+  - You are about to drop the column `feePayerOnline` on the `Event` table. All the data in the column will be lost.
+  - You are about to drop the column `feePayer` on the `Payment` table. All the data in the column will be lost.
+
+*/
+-- AlterTable
+ALTER TABLE "Event" DROP COLUMN "feePayerOnline";
+
+-- AlterTable
+ALTER TABLE "Payment" DROP COLUMN "feePayer";

backend/prisma/migrations/20260728085349_add_fee_amount_to_cashup_line/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "EventCashupLine" ADD COLUMN     "feeAmount" DOUBLE PRECISION;