properties: Ctrl+1 reveals the panel and works over clean screen

PROPERTIES only flipped the visibility flag, so a Properties pallet in
an edge's inactive group or behind auto-hide stayed out of sight. It
now opens through the dock, which brings its group forward. In clean
screen the pallet shows on top without changing its normal state;
leaving clean screen drops that overlay.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/app/dock/update.rs

@@ -553,7 +553,10 @@ impl OpenCADStudio {
     /// renderer applies before building each side's stack.
     pub(crate) fn dock_panel_visible(&self, id: crate::ui::dock::PanelId) -> bool {
         use crate::ui::dock::PanelId;
-        if self.tabs[self.active_tab].is_start || self.clean_screen {
+        if self.tabs[self.active_tab].is_start {
+            return false;
+        }
+        if self.clean_screen && !(id == PanelId::Properties && self.clean_screen_properties) {
             return false;
         }
         match id {

src/app/mod.rs

@@ -550,6 +550,8 @@ pub(super) struct OpenCADStudio {
     status_menu_tooltip_hidden: bool,
     /// Clean-screen mode: hide ribbon and side panels for a full canvas.
     clean_screen: bool,
+    /// Properties opened on top of clean screen (Ctrl+1 while it is on).
+    clean_screen_properties: bool,
     /// Quick Properties: show a compact floating property panel on selection.
     quick_properties: bool,
     /// Canvas-space cursor position where Quick Properties was last opened.
@@ -4582,6 +4584,7 @@ impl OpenCADStudio {
             otrack_cross: None,
             otrack_kind: None,
             clean_screen: false,
+            clean_screen_properties: false,
             quick_properties: false,
             quick_properties_anchor: Point::new(12.0, 12.0),
             selection_cycling: false,

src/app/update/mod.rs

@@ -4993,9 +4993,17 @@ impl OpenCADStudio {
                 Task::none()
             }
             Message::ToggleProperties => {
-                self.show_properties ^= true;
-                self.ribbon.set_properties(self.show_properties);
-                Task::none()
+                let id = crate::ui::dock::PanelId::Properties;
+                let open = !self.dock_panel_visible(id);
+                if self.clean_screen {
+                    // Shown over clean screen without changing the panel's
+                    // normal state.
+                    self.clean_screen_properties = open;
+                    if !open {
+                        return Task::none();
+                    }
+                }
+                self.dock_set_open(id, open)
             }
             Message::ToggleGraphicAttributes => {
                 let id = crate::ui::dock::PanelId::GraphicAttributes;
@@ -5504,6 +5512,7 @@ impl OpenCADStudio {
             }
             Message::ToggleCleanScreen => {
                 self.clean_screen ^= true;
+                self.clean_screen_properties = false;
                 Task::none()
             }
             Message::ToggleTransparencyDisplay => {