fix: open-issue sweep — drawing, plot, snap, layout and UI fixes

Fixes:
- Font prompt no longer lists bundled ltypeshp/qcadshp shape files (#1626)
- Wide polylines step at a discontinuous segment width; PEDIT marks the
  current vertex; keyword steps refresh the command preview (#1628)
- Radius-0 fillet drops the zero-length segment it left, so the corner
  fillets again (#1422)
- FILLET Trim / No trim option (#1558)
- True-colour wires plot in their own colour; colour picker stores the
  value it shows (#1621)
- Model tab keeps its page setup; "Save changes to layout" in Model (#1620)
- QNEW default template in Options > Files; .dwt in the open dialog
  (#1134, #1113)
- GRIDUNIT / GRIDMODE / PERSPECTIVE variables (#1618, #1524)
- PTYPE (#1433)
- ZOOM nX / nXP (#1465)
- CHSPACE between model and paper space through a viewport (#1428)
- Moving a dimension keeps its automatic text placement
- Shell icon; "&&" button labels (#1554)
- LINETYPE Load from a .lin file (#1588)
- XLINE / RAY hide the crosshair arms (#1437)
- Dynamic-input boxes keep clear of the crosshair and each other (#1546)
- Snap marker colour setting, dark default on light canvases
  (#1497, #1229, #1128)
- Dimension style precision as a 0.00 pattern dropdown (#1426)
- Node graph nodes left of the origin no longer clip away (#1592)
- Collapse button in the command history header (#1094)
- Freeze-in-current-viewport toggle in the ribbon layer list (#1466)
- Geometric Center object snap for closed polylines (#1369)

New strings translated in all 21 locales.

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

src/ui/ribbon/mod.rs

@@ -128,6 +128,8 @@ pub struct LayerInfo {
     pub visible: bool,
     pub frozen: bool,
     pub locked: bool,
+    /// Layout with an active viewport: (its Layer Manager column, frozen there).
+    pub vp_frozen: Option<(usize, bool)>,
 }
 
 /// Full-screen backdrop for an open ribbon dropdown: closes the dropdown when
@@ -1042,6 +1044,13 @@ impl Ribbon {
                     crate::ui::icons::layer_lock(ll),
                     Message::LayerToggleLock(info.name.clone()),
                 );
+                // Freeze in the current viewport only (#1466).
+                let vp_freeze = info.vp_frozen.map(|(column, frozen)| {
+                    icon_btn(
+                        crate::ui::icons::layer_vp_freeze(frozen),
+                        Message::LayerToggleVpFreeze(info.name.clone(), column),
+                    )
+                });
                 let checkmark: Element<'_, Message> =
                     crate::ui::icons::themed_check_cell(is_active);
                 let label =
@@ -1067,7 +1076,10 @@ impl Ribbon {
                     .padding([4, 4]);
 
                 container(
-                    row![checkmark, vis, freeze, lock, select]
+                    row![checkmark, vis, freeze]
+                        .push(vp_freeze)
+                        .push(lock)
+                        .push(select)
                         .spacing(5)
                         .align_y(iced::Center),
                 )

src/ui/ribbon/widgets.rs

@@ -310,7 +310,7 @@ pub(super) const TOP_HIST_GAP: f32 = 4.0;
 
 pub(crate) const UNDO_HISTORY_ID: &str = "UNDO_HISTORY";
 pub(crate) const REDO_HISTORY_ID: &str = "REDO_HISTORY";
-pub(super) const LAYER_COMBO_ID: &str = "LAYER_COMBO";
+pub(crate) const LAYER_COMBO_ID: &str = "LAYER_COMBO";
 /// Dropdown id for the tab-bar panel-density selector.
 pub(super) const COLLAPSE_MODE_ID: &str = "COLLAPSE_MODE";
 pub(super) const PROP_COLOR_ID: &str = "PROP_COLOR";