feat(ribbon): contextual Block Editor tab while editing a block

Opening the block editor brings up a Block Editor ribbon tab with
Edit / Save / Discard, Attribute Definition, and the geometric,
dimensional and parameter tools that drive parametric blocks. The tab
is only listed while a block editor session is open, and leaving the
session returns to the tab that was active before.

Refs #509

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

src/modules/block_editor/mod.rs

@@ -0,0 +1,66 @@
+//! Contextual "Block Editor" ribbon tab, shown only while a BEDIT session is
+//! open: saving or discarding the block, attribute definitions, and the
+//! constraint tools that drive parametric blocks.
+
+use crate::modules::parametric::ParametricModule;
+use crate::modules::{CadModule, IconKind, ModuleEvent, RibbonGroup, RibbonItem, ToolDef};
+
+pub struct BlockEditorModule;
+
+impl CadModule for BlockEditorModule {
+    fn id(&self) -> &'static str {
+        "block_editor"
+    }
+
+    fn title(&self) -> &'static str {
+        "Block Editor"
+    }
+
+    fn ribbon_groups(&self) -> &[RibbonGroup] {
+        static GROUPS: std::sync::OnceLock<Vec<RibbonGroup>> = std::sync::OnceLock::new();
+        GROUPS.get_or_init(|| {
+            let command = |id: &'static str, label: &'static str, icon: &'static [u8]| {
+                RibbonItem::LargeTool(ToolDef {
+                    id,
+                    label,
+                    icon: IconKind::Svg(icon),
+                    event: ModuleEvent::Command(id.to_string()),
+                })
+            };
+            let mut groups = vec![
+                RibbonGroup {
+                    title: "Open and Save",
+                    tools: vec![
+                        command(
+                            "BEDIT",
+                            "Edit Block",
+                            include_bytes!("../../../assets/icons/edit_block.svg"),
+                        ),
+                        command(
+                            "BEDIT_SAVE",
+                            "Save Block",
+                            include_bytes!("../../../assets/icons/mt_ok.svg"),
+                        ),
+                        command(
+                            "BEDIT_DISCARD",
+                            "Discard Block Edit",
+                            include_bytes!("../../../assets/icons/mt_cancel.svg"),
+                        ),
+                    ],
+                },
+                RibbonGroup {
+                    title: "Attributes",
+                    tools: vec![command(
+                        "ATTDEF",
+                        "Attribute Definition",
+                        include_bytes!("../../../assets/icons/attdef.svg"),
+                    )],
+                },
+            ];
+            // Parametric blocks are driven by the same constraints and
+            // parameters as the Parametric tab.
+            groups.extend(ParametricModule.ribbon_groups().iter().cloned());
+            groups
+        })
+    }
+}

src/modules/mod.rs

@@ -25,6 +25,7 @@ pub use ocs_plugin_api::ribbon::{
 // ── Module declarations ───────────────────────────────────────────────────
 
 pub mod annotate;
+pub mod block_editor;
 pub mod draw;
 pub mod insert;
 pub mod layout;

src/modules/registry.rs

@@ -23,6 +23,7 @@ pub fn all_modules() -> Vec<Box<dyn CadModule>> {
         Box::new(super::view::ViewModule),
         Box::new(super::manage::ManageModule),
         Box::new(super::layout::LayoutModule),
+        Box::new(super::block_editor::BlockEditorModule),
     ]
 }