Require min 1 confirmation in payment tier config.

Disallow minConfirmations: 0 for BTC and XMR tiers at startup validation, update env examples and deploy docs, and drop tx-detected UI copy and legacy tests.

backend/src/utils/invoice/toStorefrontInvoiceView.spec.ts

@@ -463,19 +463,6 @@ describe('toStorefrontInvoiceView', () => {
                 statusVariant: 'confirmed'
             });
         });
-
-        it('treats tx-detected invoices as confirmed for payment status display', async () => {
-            const payment = buildPayment({ confirmations: 0 });
-            const invoice = buildInvoice({
-                moneroDetails: buildMoneroDetails({ requiredConfirmations: 0 }),
-                payments: [payment]
-            });
-
-            const view = await toStorefrontInvoiceView(invoice);
-
-            expect(view.showRefresh).toBe(false);
-            expect(view.payments[0].confirmationStatus).toBe('Confirmed');
-        });
     });
 
     describe('overpayment', () => {