feat(catalog): dual durations, item groups, relations and branch overrides

Section 5 of the design document rejects summing service durations. "Face + bikini"
is not 15+12=27 minutes but 15+8=23 — preparation and settling the patient do not
happen twice. Seven wasted minutes times twenty appointments a day is an hour of
capacity lost daily, and AppointmentController was doing exactly that plain sum.

Each item now carries a solo duration and an additional duration. One item counts at
its solo duration and the rest at their additional; the anchor is the item with the
*largest* solo duration rather than the first one selected. Anchoring on selection
order would have let the same basket cost different amounts depending on click order,
so a patient could buy a shorter appointment by reordering. Largest-first is also
conservative: no combination is ever under-estimated, and under-estimating pushes the
next appointment on top of this one.

additional_duration_minutes stays NULL by default and the entity reads NULL as "same
as solo", so every existing service keeps behaving exactly as before — the 236
appointment-domain tests pass unchanged. The old duration_minutes column is kept and
written in step rather than renamed, because other consumers still read it.

ServiceBookingCalculator now delegates to DurationCalculator, which is the one-line
change task 00 predicted when it deliberately preserved the naive sum.

Selection rules are data, not policy: min/max per group is a number, and "bikini does
not combine with full body" is a relation. Putting either in a rules engine means
several rules per service and nobody able to explain a rejection. Validation returns
*all* errors at once rather than the first, since a user with three problems should
not make three round trips. Prerequisite cycles are rejected at write time — storing
both "A requires B" and "B requires A" would make every selection permanently invalid.

Named CatalogCategory, not ServiceCategory: that name is already an insurance enum
(outpatient/inpatient) living on ServiceItem itself, so the two would have collided in
the same file's imports.

Also fixed a defect the tests caught: breakdown() used $overrides[$id]?->… on a key
that may not exist, which warns instead of yielding null.

1175 tests / 3289 assertions. phpstan measured at 14 errors both with and without
this change (verified by stashing). Slot-mode frozen contract green.

The admin UI tab for groups and relations is not built; the checklist records it as
outstanding with a target. The backend is complete and
POST /service-selection/validate is consumable without it.

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

src/ClinicService/Repository/ItemGroupMemberRepository.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace App\ClinicService\Repository;
+
+use App\ClinicService\Entity\ItemGroup;
+use App\ClinicService\Entity\ItemGroupMember;
+use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Doctrine\Persistence\ManagerRegistry;
+
+/**
+ * @extends ServiceEntityRepository<ItemGroupMember>
+ */
+class ItemGroupMemberRepository extends ServiceEntityRepository
+{
+    public function __construct(ManagerRegistry $registry)
+    {
+        parent::__construct($registry, ItemGroupMember::class);
+    }
+
+    public function deleteForGroup(ItemGroup $group): int
+    {
+        return (int) $this->createQueryBuilder('m')
+            ->delete()
+            ->where('m.group = :group')
+            ->setParameter('group', $group)
+            ->getQuery()
+            ->execute();
+    }
+
+    /**
+     * گروه‌هایی که این آیتم‌ها در آن‌ها عضوند — برای اعتبارسنجی انتخاب، با یک کوئری.
+     *
+     * @param int[] $itemIds
+     * @return ItemGroupMember[]
+     */
+    public function findByItemIds(array $itemIds): array
+    {
+        if ($itemIds === []) {
+            return [];
+        }
+
+        return $this->createQueryBuilder('m')
+            ->addSelect('g')
+            ->join('m.group', 'g')
+            ->where('m.item IN (:ids)')
+            ->setParameter('ids', $itemIds)
+            ->getQuery()
+            ->getResult();
+    }
+}