Connect HL7 v2 orders

A scheduled exam reaches KomPACS as an HL7 v2 ORM^O01 order. IRIS converts it to a FHIR ServiceRequest with its built-in path.

Path

NIS/RIS ──ORM^O01──> HL7.Orders.In ──> ZHL7.OrderToSDA ──> SDA3 ──> ZHL7.SDA3ToFHIR ──> FHIR ServiceRequest

Production item	Class
`HL7.Orders.In`	`EnsLib.HL7.Service.HTTPService` (POC). Production: an MLLP/TCP service with TLS.
HL7 to SDA3	`ZHL7.OrderToSDA`. It calls `HS.Gateway.HL7.HL7ToSDA3` and passes PID-3 as the patient resource ID.
SDA3 to FHIR	`HS.FHIR.DTL.Util.HC.SDA3.FHIR.Process` with transform class `ZHL7.SDA3ToFHIR`. It skips the Patient entry, so the existing Patient stays.
FHIR write	`HS.FHIRServer.Interop.Operation`

PID-3: the patient ID. It must equal the FHIR Patient.id.
ORC-2: the placer order number. It becomes a ServiceRequest.identifier of type PLAC.
OBR-4: the modality with coding system DCM (for example CT, MR, PT). IRIS maps it to the DICOM OID system urn:oid:1.2.840.10008.2.16.4.

Load the two ObjectScript classes into the FHIR namespace.
Add the business service, the process and the operation to the production. Start it.
Point the NIS/RIS interface engine at the business service.
Send one test order.
Check the result with a FHIR search, not the ACK:
```
GET /fhir/r4/ServiceRequest?identifier=<placer number>
```
The HTTP service ACKs on receipt (MSA|CA). The ServiceRequest is searchable about 1 s later.

Each order also creates one Organization from MSH.
The POC HTTP service decodes the body as Latin-1. Czech diacritics in free-text fields break. Set the character set in the production before you send Czech text.