feat(secretary): implement multi-doctor assignment for clinic secretaries

- Added functionality to assign a single secretary to multiple doctors within a clinic, allowing for scoped access to appointments.
- Introduced `SecretaryService` to handle the logic for assigning and syncing doctors for a secretary.
- Updated `SecretaryController` to support multi-doctor assignment via new endpoints and modified existing ones.
- Enhanced `DoctorSecretary` entity to include secretary UUID in its serialized output.
- Implemented repository methods to facilitate the retrieval and management of doctor-secretary relationships.
- Adjusted appointment filtering in `MyAppointmentsController` to ensure secretaries only see appointments for assigned doctors.
- Created tests to validate the new multi-doctor assignment functionality and appointment access restrictions.
- Updated frontend components to support multi-select for doctors in the secretary management UI.

src/Secretary/Entity/DoctorSecretary.php

@@ -127,6 +127,7 @@ class DoctorSecretary
     {
         return [
             'uuid'          => $this->uuid,
+            'secretary_uuid' => $this->secretary->getUuid(),
             'user_name'     => $this->secretary->getRealName(),
             'mobile_number' => $this->secretary->getMobileNumber(),
             'doctor_name'   => $this->doctor->getName(),