Add MITC4 drilling diagnostics output and comparison contract

tests/reference/eigen_reference_comparison.cpp

@@ -20,6 +20,8 @@
 #include "fesa/io/abaqus/domain_mapper.h"
 #include "fesa/io/abaqus/input_reader.h"
 
+#include "mitc4_drilling_reader.h"
+
 namespace fesa::test {
 namespace {
 
@@ -385,6 +387,9 @@ Result<EigenReferenceComparisonReport> EigenReferenceComparison::Compare(
     }
 
     EigenReferenceComparisonReport report{};
+    report.drilling_diagnostics = ReadMitc4DrillingReport(file.Get());
+    if (report.drilling_diagnostics && !report.drilling_diagnostics->frames.empty())
+      Fail("schema-mismatch", "Eigen drilling diagnostics must have no equilibrium frames.");
     report.case_id = reference_case.case_id;
     report.source_step_name = frequency.source_step_name_raw;
     report.requested_mode_count = requested;