feat(layout): MVSETUP sets a drawing up for plotting

In model space MVSETUP draws the sheet border at the drawing scale
(scale factor, paper width and height) and zooms to it, or switches to
a layout. On a layout it creates viewports in a bounding area (a single
one, a 2x2 engineering set of top/front/right/isometric views, or an
array with spacing), deletes picked objects, and scales picked
viewports to a paper/model unit ratio.

A viewport's fit to the model now measures the model along the
viewport's own view direction, so side and isometric views frame it
too.

Refs #1501

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

src/app/command_driver/mod.rs

@@ -882,6 +882,13 @@ impl OpenCADStudio {
             CmdResult::ZoomToWindow { p1, p2 } => {
                 self.handle_zoom_to_window(p1, p2);
             }
+            CmdResult::CommitAndZoom { entity, p1, p2 } => {
+                self.handle_commit_entities_and_exit(vec![entity], false, false);
+                self.handle_zoom_to_window(p1, p2);
+            }
+            CmdResult::ScaleViewports { handles, factor } => {
+                self.handle_scale_viewports(handles, factor);
+            }
             CmdResult::TwistView(twist) => {
                 self.handle_twist_view(twist);
             }

src/app/command_driver/viewport.rs

@@ -447,6 +447,33 @@ impl OpenCADStudio {
             .push_output(crate::t!("Zoom Window").as_ref());
     }
 
+    /// MVSETUP Scale viewports: each picked layout viewport shows the model
+    /// at `factor` paper units per model unit. One undo step.
+    pub(in crate::app) fn handle_scale_viewports(&mut self, handles: Vec<Handle>, factor: f64) {
+        let i = self.active_tab;
+        self.tabs[i].active_cmd = None;
+        self.tabs[i].snap_result = None;
+        let handles: Vec<Handle> = handles
+            .into_iter()
+            .filter(|handle| {
+                matches!(
+                    self.tabs[i].scene.document.get_entity(*handle),
+                    Some(codec::EntityType::Viewport(viewport)) if viewport.id > 1
+                )
+            })
+            .collect();
+        if handles.is_empty() {
+            return;
+        }
+        self.push_undo_snapshot(i, "MVSETUP");
+        for handle in handles {
+            self.tabs[i]
+                .scene
+                .set_viewport_scale_factor_for(handle, factor);
+        }
+        self.tabs[i].dirty = true;
+    }
+
     /// Turn the active view about its line of sight so the drawing shows
     /// `twist` radians counter-clockwise from its untwisted orientation.
     pub(in crate::app) fn handle_twist_view(&mut self, twist: f64) {