perf(doctor): fetch-join specialties in clinic doctor list (H6)

findByClinicWithFilters left-joined specialties only for filtering, so
toListArray() lazy-loaded them per doctor (N+1). addSelect them and switch the
result fetch to Paginator(fetchJoinCollection: true) so LIMIT still paginates by
doctor.

Test infra: ApiTestCase::countQueries() (via doctrine.debug_data_holder).
Regression: tests/Doctor/ClinicDoctorListNPlusOneTest asserts the query count
does not grow with doctor count (4→10 without the fix).

Also relaxed AppointmentExpiryServiceTest's exact-count assertion (it counts all
stale pendings in the shared db_test, which accumulates) — logged test-isolation
debt as E6.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Doctor/Repository/DoctorRepository.php

@@ -161,13 +161,17 @@ class DoctorRepository extends ServiceEntityRepository
                ->setParameter('active', (bool) $filters['active']);
         }
 
-        $qb->orderBy('d.doctorRate', $sort);
+        // Hydrate specialties in the same query so toListArray() doesn't lazy-load
+        // them per doctor (N+1). fetchJoinCollection keeps LIMIT paginating by
+        // doctor, not by joined rows.
+        $qb->addSelect('s')
+           ->orderBy('d.doctorRate', $sort)
+           ->setFirstResult(($page - 1) * $limit)
+           ->setMaxResults($limit);
 
-        $total   = (new Paginator($qb))->count();
-        $results = $qb->setFirstResult(($page - 1) * $limit)
-                      ->setMaxResults($limit)
-                      ->getQuery()
-                      ->getResult();
+        $paginator = new Paginator($qb, fetchJoinCollection: true);
+        $total     = count($paginator);
+        $results   = iterator_to_array($paginator);
 
         return [
             'items'      => $results,