Add Orthanc DICOM server provider

[Liohtml]

Description

Add a data provider for Orthanc - a popular open-source DICOM server used in many hospitals and research institutions.

How it works

Orthanc exposes a REST API for querying and retrieving DICOM files:

• GET /patients - list patients
• GET /studies/{id} - get study info
• GET /series/{id} - get series info
• GET /instances/{id}/file - download DICOM file

Files to create

• src/medcheck/providers/orthanc.py - implement DataProvider interface
• tests/unit/test_providers/test_orthanc.py

Reference

• Orthanc REST API docs
• See src/medcheck/providers/local.py for provider pattern
• See src/medcheck/providers/base.py for the interface

URL patterns for auto-detect

/orthanc/, port 8042 (default Orthanc port)