Layouts: a viewport on first opening (LAYOUTCREATEVIEWPORT)

A layout opened for the first time - one whose sheet viewport had to be
made, or one created in this session - gets a viewport centred on the
printable area, 0.8 of its width and height, zoomed to the model's
extents, while LAYOUTCREATEVIEWPORT is on. The profile variable takes
ON/OFF or 1/0 and is kept with the settings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/update/file.rs

@@ -796,6 +796,7 @@ impl OpenCADStudio {
             surface_associativity: crate::scene::model::sweep_model::surface_associativity(),
             ucs_ortho: crate::modules::view::view_cmd::ucs_ortho(),
             ucs_view: crate::modules::view::view_cmd::ucs_view(),
+            layout_create_viewport: crate::scene::layout_create_viewport(),
             ncopy_bind: self.ncopy_bind,
             cursor_type: self.cursor_type,
             crosshair_color: self.crosshair_color,
@@ -911,6 +912,7 @@ impl OpenCADStudio {
         crate::scene::model::sweep_model::set_surface_associativity(s.surface_associativity);
         crate::modules::view::view_cmd::set_ucs_ortho(s.ucs_ortho);
         crate::modules::view::view_cmd::set_ucs_view(s.ucs_view);
+        crate::scene::set_layout_create_viewport(s.layout_create_viewport);
         self.ncopy_bind = s.ncopy_bind;
         self.cursor_type = s.cursor_type;
         self.crosshair_color = s.crosshair_color;