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 <[email protected]>

src/app/update/command.rs

@@ -727,6 +727,16 @@ pub(super) fn on_tab_close(&mut self, idx: usize) -> Task<Message> {
                         crate::app::expr_eval::eval_to_string(&raw)
                     };
                     self.command_line.input.clear();
+                    // Remember the token for the context menu's Recent Input
+                    // list (prose steps excluded: a table cell or text body
+                    // is not a reusable value).
+                    let is_prose = self.tabs[i]
+                        .active_cmd
+                        .as_ref()
+                        .is_some_and(|c| c.input_kind().is_free_text());
+                    if !is_prose {
+                        self.command_line.record_recent_input(&text);
+                    }
 
                     // Offer the typed text to the command's option handler
                     // first (keywords like PLINE's A/L/C, a radius, …). If it