feat(loyalty): pay own orders with EnakPoint from the app

Adds POST /customer/orders/:id/pay-with-points (docs/prd-point-coin.md F9,
PC-306) for the customer app and self-order. It uses the same payment path
as the cashier, approved by the customer's PIN instead of a code: the
session alone is not enough (K8), and a wrong PIN takes nothing and counts
toward the lock.

A customer can pay only their own order; any other order, and one that
does not exist, answer 404 alike, so the endpoint does not reveal other
customers' orders. The method is the organization's EnakPoint method, no
cashier is recorded, and settling the order triggers earning through the
same onOrderPaid hook as every other payment.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/processor/point_payment_db_test.go

@@ -91,7 +91,7 @@ func newPointPaymentEnv(t *testing.T) *pointPaymentEnv {
 		txManager:          txm,
 	}
 	e.orders.SetLoyalty(NewEarningProcessor(repository.NewEarningRepository(db), settings, wallet, txm))
-	e.orders.SetPointPayments(e.payments, e.codes)
+	e.orders.SetPointPayments(e.payments, e.codes, pinVerifierFake{good: "482913"})
 
 	// The outlet earns 1 EnakPoint per Rp 100 and accepts EnakPoint.
 	s, err := settings.Outlet(context.Background(), e.outlet)
@@ -332,3 +332,45 @@ func TestPointPayment_ConcurrentForOneCustomer(t *testing.T) {
 		assert.NotEqual(t, customer, d.CustomerID, d.Check)
 	}
 }
+
+func TestPointPayment_InApp(t *testing.T) {
+	e := newPointPaymentEnv(t)
+	owner := e.customerWith(100000)
+	stranger := e.customerWith(100000)
+	order := e.order(owner, 60000)
+	info := models.CustomerPinRequestInfo{}
+
+	// Another customer cannot pay it, and is not told it exists.
+	_, err := e.orders.PayWithPointsInApp(e.ctx, stranger, order, 1000, "482913", info)
+	assert.ErrorIs(t, err, repository.ErrPointPaymentOrderNotFound)
+	_, err = e.orders.PayWithPointsInApp(e.ctx, owner, uuid.New(), 1000, "482913", info)
+	assert.ErrorIs(t, err, repository.ErrPointPaymentOrderNotFound)
+
+	// The session alone is not enough: a wrong PIN takes nothing.
+	_, err = e.orders.PayWithPointsInApp(e.ctx, owner, order, 1000, "000000", info)
+	var pe *PinError
+	require.ErrorAs(t, err, &pe)
+	assert.Equal(t, PinErrInvalid, pe.Code)
+	assert.Equal(t, int64(100000), e.balance(owner))
+
+	// The owner pays part, then the rest, with the same rules as at the cashier.
+	payment, err := e.orders.PayWithPointsInApp(e.ctx, owner, order, 10000, "482913", info)
+	require.NoError(t, err)
+	assert.Equal(t, int64(10000), *payment.PointsUsed)
+	status, remaining := e.orderState(order)
+	assert.Equal(t, "partial", status)
+	assert.Equal(t, 50000.0, remaining)
+
+	_, err = e.orders.PayWithPointsInApp(e.ctx, owner, order, 50001, "482913", info)
+	assert.ErrorIs(t, err, ErrPointPaymentRejected, "not more than what is left")
+	_, err = e.orders.PayWithPointsInApp(e.ctx, owner, order, 50000, "482913", info)
+	require.NoError(t, err)
+	status, _ = e.orderState(order)
+	assert.Equal(t, "completed", status)
+	assert.Equal(t, int64(40000), e.balance(owner))
+	assert.Equal(t, int64(100000), e.balance(stranger))
+
+	var createdBy *string
+	require.NoError(t, e.db.Raw(`SELECT created_by_user::text FROM wallet_transactions WHERE customer_id = ? AND type = 'PAYMENT' LIMIT 1`, owner).Scan(&createdBy).Error)
+	assert.Nil(t, createdBy, "no cashier took an in-app payment")
+}