feat(package): session packages backed by a credit ledger

"Six laser sessions" is the common case in an aesthetics clinic: the patient
pays once and books the sessions later.

Credit is a ledger, not a counter. No table has a remaining/used_count column
and a schema test enforces that — the balance is always SUM(delta) over
append-only rows, so every number a patient sees has a full history behind it.
Corrections are new rows, never edits.

- purchase / consume / refund / adjustment / expiry, each with a reason, an
  author and the appointment it belongs to
- consume happens in confirm(), never in quote(): if the preview consumed, a
  page refresh would cost the patient a session
- cancelling adds a refund row; the consume row stays
- FIFO across a patient's packages — the oldest is closest to expiring
- an empty package is not an error, it just does not apply and the patient pays
- adjust/expire need a doctor or clinic role, and adjust always needs a reason
- app:package:expire writes the closing row so "where did my 3 sessions go?"
  always has an answer

Consume takes a pessimistic lock on the one package row. That is the opposite
of task 07's slot buckets, and docs/api/package.md carries the table explaining
why, so nobody unifies them later.

Idempotency checks for an existing consume row before inserting rather than
catching the unique violation: in Doctrine that exception closes the
EntityManager and burns the rest of the request. The unique key stays as the
last line of defence.

Admin: PackagesPage, a packages tab on the patient record, and a ledger page
whose running-balance column shows where the final number came from.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/Appointment/Booking/Service/BookingService.php

@@ -6,6 +6,8 @@ use App\Appointment\Availability\Entity\ResourceOccupancy;
 use App\Appointment\Booking\Entity\AppointmentHold;
 use App\Appointment\Booking\Entity\AppointmentSegment;
 use App\Appointment\Entity\Appointment;
+use App\Package\Service\CreditLedgerService;
+use App\Package\Service\PackageConsumptionService;
 use App\Shared\Constant\ErrorCodes;
 use App\Shared\Exception\AppException;
 use Doctrine\ORM\EntityManagerInterface;
@@ -20,8 +22,10 @@ use Doctrine\ORM\EntityManagerInterface;
 final class BookingService
 {
     public function __construct(
-        private readonly HoldService            $holds,
-        private readonly EntityManagerInterface $em,
+        private readonly HoldService                $holds,
+        private readonly PackageConsumptionService  $packages,
+        private readonly CreditLedgerService        $credits,
+        private readonly EntityManagerInterface     $em,
     ) {}
 
     /**
@@ -54,6 +58,10 @@ final class BookingService
 
         $this->em->flush();
 
+        // مصرف اعتبار **اینجا**ست نه در پیش‌نمایش قیمت: تنها لحظه‌ای که نوبت واقعاً
+        // وجود دارد. کلید یکتای دفتر هم تضمین می‌کند اجرای دوباره جلسهٔ دوم نخورد.
+        $this->packages->consumeFor($appointment);
+
         return $appointment;
     }
 
@@ -96,6 +104,9 @@ final class BookingService
 
         $this->holds->release($occupancies);
 
+        // ردیف `consume` **حذف نمی‌شود**؛ بازگشت یک ردیف تازه است تا تاریخچه بماند.
+        $this->credits->refund($appointment);
+
         return count($occupancies);
     }