feat(ui): compatible right-click context menu driven by command options

The viewport context menu is now built from a pure model
(ui::popup::context_menu) rendered by the overlay: while a command runs it
offers Enter / Cancel / every keyword of the command's options() with the
keyword shown as a hint, a Recent Input submenu and M2P; when idle it offers
Repeat, Recent Input, Clipboard, Undo/Redo with history labels, the edit
block (Erase/Move/Copy/Scale/Rotate/Mirror/Draw Order), Isolate, Pan/Zoom,
selection tools, Properties and Options. The default row is anchored under
the pointer and the menu is keyboard-navigable (arrows, Enter, mnemonic
letters; any other key closes it and types into the command line).

Right-click behaviour is a user preference (Options → User Preferences,
SHORTCUTMENU / SHORTCUTMENUDURATION): shortcut menu (commercial solutions default),
time-sensitive, or the previous Enter-first cycle.

LINE gains options() (Close/Undo/eXit).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/app/view/modal.rs

@@ -297,6 +297,8 @@ impl OpenCADStudio {
                             show_viewcube: self.show_viewcube,
                             show_ucs_icon: self.show_ucs_icon,
                             ucs_icon_at_origin: self.ucs_icon_at_origin,
+                            right_click_mode: self.right_click_mode,
+                            right_click_hold_ms: self.right_click_hold_ms,
                         },
                         crate::ui::window::options::spacemouse::view(
                             self.spacemouse_preferences, self.spacemouse.status(),