fix(sonar): properly separate test files from source analysis

Add test file exclusions from source analysis and explicitly declare
test file paths. This ensures test code duplication doesn't count
towards the quality gate's duplication threshold.

Author: leifj

sonar-project.properties

@@ -7,9 +7,11 @@ sonar.organization=sunet
 
 # Source configuration
 sonar.sources=.
-sonar.exclusions=vendor/**,**/testdata/**
+sonar.exclusions=vendor/**,**/testdata/**,**/*_test.go
+sonar.tests=.
+sonar.test.inclusions=**/*_test.go
 
-# Exclude test files from duplication detection
+# Exclude test files from duplication detection (CPD - Copy Paste Detection)
 # Test code intentionally contains similar patterns for comprehensive coverage
 sonar.cpd.exclusions=**/*_test.go