feat(options): menu bar, ribbon and HPASSOC switches; see-through command line by default

Options > Display gains Window Elements with "Show the menu bar"
(MENUBAR) and "Show the ribbon" (RIBBON / RIBBONCLOSE); Options > User
Preferences gains a Hatch switch for HPASSOC. The command line now
starts at 80 % opacity so the drawing shows through it.

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

src/app/settings.rs

@@ -904,7 +904,7 @@ impl Default for UserSettings {
             language: crate::i18n::Language::default(),
             cliprompt_lines: 3,
             commandline_fade_ms: 3000,
-            command_line_opacity: 100,
+            command_line_opacity: 80,
             snap_spacing_x: 10.0,
             snap_spacing_y: 10.0,
             grid_spacing_x: 10.0,