perf(db): add missing indexes (appointment expiry, session dates, user status)

- appointments(status, expires_at): the per-minute expiry scheduler filtered on
  these with no covering index
- patient_sessions(created_at): dashboard revenue range scans
- users(status): admin user-list filter

PatientRecord(entity_type,entity_id) already covered by its unique constraint;
UserActiveContext.user_id is the PK — neither needed a new index.

src/Patient/Entity/PatientSession.php

@@ -11,6 +11,7 @@ use Symfony\Component\Uid\Uuid;
 
 #[ORM\Entity(repositoryClass: PatientSessionRepository::class)]
 #[ORM\Table(name: 'patient_sessions')]
+#[ORM\Index(columns: ['created_at'], name: 'idx_patient_sessions_created_at')]
 class PatientSession
 {
     #[ORM\Id]