#14772 Python: Add Case.replace_grid and forward replaceCase to it

First step in modernizing the command file interface: move the
implementation of legacy Ricf commands into object-oriented Rimc
methods, and let the Ricf command forward to them.

- Add RimCase_replaceGrid (PdmVoidObjectMethod on RimCase) with
  NewGridFile and optional ProjectFile parameters. Works for both
  Eclipse result cases and GeoMech cases. Generated in Python as
  Case.replace_grid().
- Add RicfCommandForwarding helpers for resolving ids to objects and
  converting std::expected results to PdmScriptResponse.
- RicfSingleCaseReplace::execute() now resolves the case and the
  executor's last project path, then forwards to RimCase_replaceGrid.
  Command file syntax and Commands.proto are unchanged.
- Case.replace() in Python is kept as a thin wrapper over
  replace_grid() and emits a DeprecationWarning.

ApplicationLibCode/CommandFileInterface/RicfCommandForwarding.cpp

@@ -0,0 +1,90 @@
+/////////////////////////////////////////////////////////////////////////////////
+//
+//  Copyright (C) 2026- Equinor ASA
+//
+//  ResInsight is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+//
+//  ResInsight is distributed in the hope that it will be useful, but WITHOUT ANY
+//  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+//  FITNESS FOR A PARTICULAR PURPOSE.
+//
+//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html>
+//  for more details.
+//
+/////////////////////////////////////////////////////////////////////////////////
+
+#include "RicfCommandForwarding.h"
+
+#include "RiaLogging.h"
+
+#include "Rim3dView.h"
+#include "RimCase.h"
+#include "RimEclipseResultCase.h"
+#include "RimProject.h"
+
+#include "cafPdmObjectHandle.h"
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+std::expected<RimCase*, QString> RicfForwarding::findCase( int caseId )
+{
+    RimProject* project = RimProject::current();
+    if ( !project ) return std::unexpected( "No project is available." );
+
+    std::vector<RimCase*> allCases = project->allGridCases();
+    if ( caseId < 0 )
+    {
+        // Matches RiaProjectModifier::firstCaseId(): the first occurrence is the first Eclipse result case
+        for ( RimCase* rimCase : allCases )
+        {
+            if ( dynamic_cast<RimEclipseResultCase*>( rimCase ) ) return rimCase;
+        }
+        return std::unexpected( "No Eclipse result cases found in project." );
+    }
+
+    for ( RimCase* rimCase : allCases )
+    {
+        if ( rimCase && rimCase->caseId() == caseId ) return rimCase;
+    }
+
+    return std::unexpected( QString( "Could not find case with ID %1" ).arg( caseId ) );
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+std::expected<Rim3dView*, QString> RicfForwarding::findView( RimCase* rimCase, int viewId )
+{
+    if ( !rimCase ) return std::unexpected( "No case given when looking up view." );
+
+    for ( Rim3dView* view : rimCase->views() )
+    {
+        if ( view && view->id() == viewId ) return view;
+    }
+
+    return std::unexpected( QString( "Could not find view with ID %1 in case %2" ).arg( viewId ).arg( rimCase->caseId() ) );
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+caf::PdmScriptResponse RicfForwarding::toScriptResponse( const std::expected<caf::PdmObjectHandle*, QString>& result, const QString& commandName )
+{
+    if ( !result.has_value() ) return errorResponse( result.error(), commandName );
+
+    return caf::PdmScriptResponse();
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+caf::PdmScriptResponse RicfForwarding::errorResponse( const QString& message, const QString& commandName )
+{
+    QString fullMessage = QString( "%1: %2" ).arg( commandName ).arg( message );
+    RiaLogging::error( fullMessage.toStdString() );
+    return caf::PdmScriptResponse( caf::PdmScriptResponse::COMMAND_ERROR, fullMessage );
+}