Apply available credit to any at-booking charge, not just scheduled

A payer's account credit should offset any charge raised at booking, so
drop the scheduled-only guard. Covers the one-time pay-now flow too.

Co-authored-by: anthropic/claude-opus-4-8

src/Booking/LessonBooker.php

@@ -196,8 +196,8 @@ class LessonBooker {
 				payerId: $payerId
 			);
 
-			// Apply any available credit to a scheduled charge raised at booking.
+			// Apply any available credit to a charge raised at booking.
-			if ( $offering->isScheduledBilling() && null !== $payment && null !== $payment->id && Payment::STATUS_PENDING === $payment->status ) {
+			if ( null !== $payment && null !== $payment->id && Payment::STATUS_PENDING === $payment->status ) {
 				$this->payments->applyCredits( $payerId, [ $payment ] );
 				$payment = $this->payments->findPayment( (int) $payment->id ) ?? $payment;
 			}

tests/Unit/Booking/AdminBookingTest.php

@@ -48,6 +48,12 @@ class AdminBookingTest extends TestCase
         $this->bookings     = Mockery::mock(BookingRepository::class);
         $this->offerings    = Mockery::mock(OfferingRepository::class);
         $this->payments     = Mockery::mock(PaymentService::class);
+        // A charge raised at booking has the payer's credit applied before it
+        // settles. The default holds no balance and re-reads the same payment.
+        $this->payments->shouldReceive('applyCredits')->andReturn([])->byDefault();
+        $this->payments->shouldReceive('findPayment')->andReturnUsing(
+            static fn (int $id): ?Payment => null
+        )->byDefault();
         $this->guardians    = Mockery::mock(GuardianService::class);
         $this->guardians->shouldReceive('payerFor')->andReturnUsing(static fn (int $id): int => $id)->byDefault();
 

tests/Unit/Booking/BookingEndpointTest.php

@@ -57,9 +57,9 @@ class BookingEndpointTest extends TestCase
         // Crediting a cancelled paid lesson is exercised in dedicated tests; other
         // cancellation paths simply allow the call.
         $this->payments->shouldReceive('creditForCancelledLesson')->andReturn(null)->byDefault();
-        // A charge-at-booking scheduled lesson (an add-on to an already-billed month)
+        // A charge raised at booking applies the payer's credit before it settles.
-        // applies the payer's credit before it settles. The default holds no balance
+        // The default holds no balance and re-reads the same payment; the
-        // and re-reads the same payment; the same-month-rebook test overrides both.
+        // same-month-rebook test overrides both.
         $this->payments->shouldReceive('applyCredits')->andReturn([])->byDefault();
         $this->payments->shouldReceive('findPayment')->andReturnUsing(
             static fn (int $id): ?Payment => null