#13807 Add a case-less Data View and merge it with Eclipse views in the tree

- Added RimGeneric3dView, a 3D view that is not tied to any grid case,
  useful for wells, surfaces and other data not requiring a reservoir
  grid. The view supports a custom name.
- Introduced RimGenericViewCollection, a new top-level collection that
  holds both Eclipse views and RimGeneric3dView instances. It overrides
  defineUiTreeOrdering() to display both types as a single flat list
  under the top-level 'Views' node.
- RimOilField now exposes a single genericViewCollection instead of a
  plain eclipseViewCollection field.
- RimEclipseViewCollection is unchanged and continues to be used for
  per-case and ensemble view collections.
- Updated RimEclipseCase::globalViewCollection() and related helpers to
  use RimGenericViewCollection, and added matching overloads in
  RicNewViewFeature for creating eclipse views from the merged
  collection.
- Added RicNewGenericDataViewFeature to create a new generic data view
  from the context menu.

ApplicationLibCode/Commands/RicNewGenericDataViewFeature.cpp

@@ -0,0 +1,92 @@
+/////////////////////////////////////////////////////////////////////////////////
+//
+//  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 "RicNewGenericDataViewFeature.h"
+
+#include "RimGeneric3dView.h"
+#include "RimGenericViewCollection.h"
+#include "RimOilField.h"
+#include "RimProject.h"
+
+#include "Riu3DMainWindowTools.h"
+
+#include <QAction>
+
+CAF_CMD_SOURCE_INIT( RicNewGenericDataViewFeature, "RicNewGenericDataViewFeature" );
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+bool RicNewGenericDataViewFeature::isCommandEnabled() const
+{
+    // A data view is useful even in an empty project; content can be added afterwards.
+    return true;
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+void RicNewGenericDataViewFeature::onActionTriggered( bool isChecked )
+{
+    createDataView();
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+void RicNewGenericDataViewFeature::setupActionLook( QAction* actionToSetup )
+{
+    actionToSetup->setIcon( QIcon( ":/3DWindow.svg" ) );
+    actionToSetup->setText( "New Generic View" );
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+RimGeneric3dView* RicNewGenericDataViewFeature::createInitialViewIfNeeded()
+{
+    auto proj = RimProject::current();
+    if ( !proj ) return nullptr;
+
+    // Only auto-create when the project has no 3D view at all, mirroring RicNewSeismicViewFeature
+    if ( !proj->allViews().empty() ) return nullptr;
+
+    return createDataView();
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+RimGeneric3dView* RicNewGenericDataViewFeature::createDataView()
+{
+    auto proj = RimProject::current();
+    if ( !proj ) return nullptr;
+
+    auto oilField = proj->activeOilField();
+    if ( !oilField || !oilField->genericViewCollection() ) return nullptr;
+
+    auto view = oilField->genericViewCollection()->addGenericView();
+    if ( !view ) return nullptr;
+
+    oilField->genericViewCollection()->updateAllRequiredEditors();
+    view->scheduleCreateDisplayModelAndRedraw();
+
+    Riu3DMainWindowTools::selectAsCurrentItem( view );
+
+    return view;
+}