#13467 Add model padding functionality for sector model export

Add Z-direction padding support for sector models based on OPM-Flow's
padmodel.cpp. This feature enables users to add padding layers above
and/or below the exported sector model grid.

Adapts padmodel.cpp from
https://github.com/hnil/opm-flowgeomechanics/blob/geomech_hypre_cgal/examples/padmodel.cpp
Commit: 5ee483e

Fixes #13467.

ApplicationLibCode/ReservoirDataModel/SimulationFile/RigSimulationInputTool.cpp

@@ -21,6 +21,9 @@
 #include "RiaLogging.h"
 #include "RiaNncDefines.h"
 
+#include "RigModelPaddingSettings.h"
+#include "RigPadModel.h"
+
 #include "RifEclipseInputFileTools.h"
 #include "RifOpmDeckTools.h"
 #include "RifOpmFlowDeckFile.h"
@@ -152,6 +155,15 @@ std::expected<void, QString> RigSimulationInputTool::exportSimulationInput( RimE
         return result;
     }
 
+    // Apply model padding if enabled
+    if ( settings.paddingSettings().isEnabled() )
+    {
+        if ( auto result = applyModelPadding( deckFile, settings.paddingSettings() ); !result )
+        {
+            return result;
+        }
+    }
+
     // Remove SKIP keywords that were used as placeholders for filtered-out keywords
     deckFile.removeKeywords( "SKIP" );
 
@@ -1777,3 +1789,12 @@ std::expected<void, QString> RigSimulationInputTool::exportEditNncKeyword( RimEc
 
     return {};
 }
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+std::expected<void, QString> RigSimulationInputTool::applyModelPadding( RifOpmFlowDeckFile&            deckFile,
+                                                                        const RigModelPaddingSettings& paddingSettings )
+{
+    return RigPadModel::extendGrid( deckFile, paddingSettings );
+}