feat(ui): classic pull-down menu bar and ribbon toggle

MENUBAR 1 shows File, Edit, View, Insert, Format, Tools, Draw,
Dimension, Modify, Parametric and Help menus above the ribbon; every
entry runs an existing command, and a test keeps each entry pointing at
a registered command. RIBBONCLOSE hides the ribbon and RIBBON brings it
back, so the menus can replace it. Both choices persist.

Also translates the "File" label, which every locale had left in
English.

Refs #1450

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

src/app/view/mod.rs

@@ -2020,7 +2020,10 @@ bg={bg_ms:.1}ms n={view_count}"
             // Clean-screen mode drops the ribbon for a full-canvas view; the
             // status bar stays so the mode can be toggled back off.
             let mut col = column![];
-            if !self.clean_screen {
+            if !self.clean_screen && self.show_menu_bar {
+                col = col.push(crate::ui::menu_bar::view());
+            }
+            if !self.clean_screen && !self.ribbon_closed {
                 col = col.push(self.ribbon.view(
                     is_paper,
                     self.tabs[self.active_tab].is_start,