feat(statusbar): selection filtering by object type (FILTER pill)

Add a per-type selection filter to the scene: the FILTER pill opens a
checklist of the entity types in the layout, and unchecking a type
excludes it from interactive picking (click, box and lasso selection all
honour it). The pill lights up while any type is filtered out.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/app/mod.rs

@@ -177,6 +177,8 @@ pub(super) struct OpenCADStudio {
     units_popup_open: bool,
     /// True while the Isolate pill's action menu is open.
     isolate_popup_open: bool,
+    /// True while the selection-filter type picker is open.
+    selection_filter_popup_open: bool,
     /// Clean-screen mode: hide ribbon and side panels for a full canvas.
     clean_screen: bool,
     /// Quick Properties: show a compact floating property panel on selection.
@@ -756,6 +758,12 @@ pub enum Message {
     ToggleTransparencyDisplay,
     /// Toggle the Quick Properties floating panel.
     ToggleQuickProperties,
+    /// Toggle the selection-filter type picker open/closed.
+    ToggleSelectionFilterPopup,
+    /// Close the selection-filter type picker.
+    CloseSelectionFilterPopup,
+    /// Include/exclude an entity type from interactive selection.
+    ToggleSelectionFilterType(String),
     /// Toggle the drawing-units picker open/closed.
     ToggleUnitsPopup,
     /// Close the drawing-units picker.
@@ -1225,6 +1233,7 @@ impl OpenCADStudio {
             statusbar_menu_open: false,
             units_popup_open: false,
             isolate_popup_open: false,
+            selection_filter_popup_open: false,
             statusbar_config: crate::ui::statusbar_config::StatusBarConfig::load(),
             clean_screen: false,
             quick_properties: false,

src/app/update.rs

@@ -2889,6 +2889,8 @@ impl OpenCADStudio {
                                 vp_mat,
                                 bounds,
                             ));
+                            // Selection filter: keep only allowed types.
+                            handles.retain(|&h| self.tabs[i].scene.passes_selection_filter(h));
                             self.tabs[i].scene.deselect_all();
                             for h in &handles {
                                 self.tabs[i].scene.select_entity(*h, false);
@@ -2932,6 +2934,9 @@ impl OpenCADStudio {
                                     // body, not just the thin projected edges.
                                     self.tabs[i].scene.mesh_click_hit(p, vp_mat, bounds)
                                 });
+                            // Selection filter: drop a pick whose type is excluded.
+                            let hit =
+                                hit.filter(|&h| self.tabs[i].scene.passes_selection_filter(h));
                             if let Some(handle) = hit {
                                 // Individual picks accumulate (issue #47):
                                 // each plain click adds to the selection,
@@ -2980,6 +2985,8 @@ impl OpenCADStudio {
                                 vp_mat,
                                 bounds,
                             ));
+                            // Selection filter: keep only allowed types.
+                            handles.retain(|&h| self.tabs[i].scene.passes_selection_filter(h));
                             self.tabs[i].scene.deselect_all();
                             for h in &handles {
                                 self.tabs[i].scene.select_entity(*h, false);
@@ -3594,6 +3601,21 @@ impl OpenCADStudio {
                 self.quick_properties ^= true;
                 Task::none()
             }
+            Message::ToggleSelectionFilterPopup => {
+                self.selection_filter_popup_open ^= true;
+                Task::none()
+            }
+            Message::CloseSelectionFilterPopup => {
+                self.selection_filter_popup_open = false;
+                Task::none()
+            }
+            Message::ToggleSelectionFilterType(name) => {
+                let f = &mut self.tabs[self.active_tab].scene.selection_filter;
+                if !f.remove(&name) {
+                    f.insert(name);
+                }
+                Task::none()
+            }
             Message::ToggleUnitsPopup => {
                 self.units_popup_open ^= true;
                 Task::none()

src/app/view.rs

@@ -1173,6 +1173,7 @@ impl OpenCADStudio {
                         tab.scene.is_isolation_active(),
                         tab.scene.transparency_display,
                         self.quick_properties,
+                        tab.scene.selection_filter_active(),
                         &self.statusbar_config,
                     )
                 })
@@ -1232,6 +1233,21 @@ impl OpenCADStudio {
             iced::widget::Space::new().width(0).height(0).into()
         };
 
+        let sel_filter_layer: Element<'_, Message> = if self.selection_filter_popup_open {
+            let types: Vec<String> = tab
+                .scene
+                .entity_type_names_in_layout()
+                .into_iter()
+                .map(|s| s.to_string())
+                .collect();
+            crate::ui::selection_filter_popup::selection_filter_popup_overlay(
+                types,
+                &tab.scene.selection_filter,
+            )
+        } else {
+            iced::widget::Space::new().width(0).height(0).into()
+        };
+
         let dropdown_layer: Element<'_, Message> = self
             .ribbon
             .dropdown_overlay(
@@ -1270,6 +1286,7 @@ impl OpenCADStudio {
             statusbar_menu_layer,
             units_layer,
             isolate_layer,
+            sel_filter_layer,
             dropdown_layer,
             layout_ctx_layer,
             qselect_layer,