feat(pipeline): add CRTDL preprocessing for DIMP enrichment

[trobanga]

Summary

Add capability to enrich CRTDL files with additional attributes required by DIMP (pseudonymization) before sending them to TORCH.

• Add/update attributes in existing CRTDL groups by groupReference
• Create new groups when addGroupIfNotExists: true
• Resolve linkedGroups profile URLs to group IDs
• Support both external JSON file and inline YAML configuration
• Save enriched CRTDL to job directory for debugging/auditing

Files created:

• internal/models/crtdl_preprocessing.go: Config and enrichment models
• internal/services/crtdl_preprocessor.go: Pure enrichment functions
• tests/unit/crtdl_preprocessor_test.go: 20 comprehensive unit tests

Closes #75

Test plan

• All 20 new unit tests pass
• Full test suite passes (make test)
• Code compiles without errors
• Manual testing with sample CRTDL file and enrichment config

[codecov-commenter]

Codecov Report

❌ Patch coverage is 85.43417% with 52 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.78%. Comparing base (cfff7f3) to head (f3cdaf3).

Files with missing lines	Patch %	Lines
internal/services/torch_client.go	54.54%	20 Missing and 5 partials ⚠️
internal/models/crtdl_preprocessing.go	87.59%	9 Missing and 7 partials ⚠️
internal/pipeline/import.go	78.04%	4 Missing and 5 partials ⚠️
internal/services/crtdl_preprocessor.go	98.27%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #122      +/-   ##
==========================================
- Coverage   84.78%   84.78%   -0.01%     
==========================================
  Files          48       50       +2     
  Lines        5173     5514     +341     
==========================================
+ Hits         4386     4675     +289     
- Misses        598      632      +34     
- Partials      189      207      +18     

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[juliangruendner]

this does not seem to do anything -

when using this enrichment file:

[
  {
    "group_reference": "https://www.medizininformatik-initiative.de/fhir/core/modul-fall/StructureDefinition/KontaktGesundheitseinrichtung",
    "add_group_if_not_exists": true,
    "attributes_to_add": [
      {
        "attributeRef": "Encounter.class",
        "mustHave": false
      },
      {
        "attributeRef": "Encounter.status",
        "mustHave": false
      },
      {
        "attributeRef": "Encounter.serviceType",
        "mustHave": false
      }
    ]
  }
]

the group does not appear in the enriched CRTDL

[juliangruendner]

the following enrichment config does not lead to the group being added if it does not exist in the CRTDL

[
  {
    "groupReference": "https://www.medizininformatik-initiative.de/fhir/core/modul-person/StructureDefinition/PatientPseudonymisiert",
    "addGroupIfNotExists": true,
    "attributesToAdd": [
      {
        "attributeRef": "Patient.identifier",
        "mustHave": false
      }
    ]
  },
  {
    "groupReference": "https://www.medizininformatik-initiative.de/fhir/core/modul-fall/StructureDefinition/KontaktGesundheitseinrichtung",
    "addGroupIfNotExists": true,
    "attributesToAdd": [
      {
        "attributeRef": "Encounter.identifier",
        "mustHave": false
      }
    ]
  }
]