#13883 SummaryEnsemble: Replace deleteChildrenAsync with synchronous delete to fix race

deleteChildrenAsync() spawns a std::thread that deletes old RimFileSummaryCase
objects concurrently with the OpenMP parallel loop in loadFileSummaryCaseData().
#pragma omp critical only synchronizes OMP threads, not std::threads, so OPM/HDF5
library state was accessed simultaneously from both, causing crashes.

Replace with clearWithoutDelete() + synchronous delete to preserve the observer
signal disconnection fix from #12262 while eliminating the thread race.

ApplicationLibCode/ProjectDataModel/Summary/RimSummaryEnsemble.cpp

@@ -202,7 +202,13 @@ RimSummaryCase* RimSummaryEnsemble::firstSummaryCase() const
 //--------------------------------------------------------------------------------------------------
 void RimSummaryEnsemble::replaceCases( const std::vector<RimSummaryCase*>& summaryCases, bool notifyChange )
 {
-    m_cases.deleteChildrenAsync();
+    // Delete synchronously to prevent a race between the std::thread spawned by
+    // deleteChildrenAsync() and any active OpenMP parallel loop in loadFileSummaryCaseData().
+    // clearWithoutDelete() disconnects observer signals first (preserves the fix for #12262).
+    auto casesToDelete = m_cases.childrenByType();
+    m_cases.clearWithoutDelete();
+    for ( auto* c : casesToDelete )
+        delete c;
 
     if ( summaryCases.empty() ) return;