Block Definition dialog: preview, empty-block band, open in editor

The name card draws the selected objects, or the existing definition the
name picks. OK with no objects shows an in-window band offering to select
objects or to define an empty block. A switch opens the new block in the
block editor once it is defined; it is remembered with the other dialog
choices. Automation gains block_def_dialog.

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

src/app/commands/blocks.rs

@@ -61,7 +61,11 @@ impl OpenCADStudio {
             remembered.objects_on_screen = state.objects_specify_onscreen;
             remembered.mode = state.object_mode;
             remembered.allow_exploding = state.allow_exploding;
+            remembered.open_in_editor = state.open_in_editor;
         }
+        self.block_definition_open_editor = state
+            .open_in_editor
+            .then(|| state.name.trim().to_string());
         self.persist_settings_if_changed();
         let i = self.active_tab;
         let base_point = state.parse_base_point();
@@ -122,6 +126,32 @@ impl OpenCADStudio {
         )
     }
 
+    /// Draw the selected objects, or else the existing definition the name
+    /// picks, in the Block Definition dialog's name card.
+    pub(in crate::app) fn refresh_block_definition_preview(&mut self) {
+        let scene = &self.tabs[self.active_tab].scene;
+        let Some(state) = self.block_definition.as_mut() else {
+            return;
+        };
+        state.preview = if state.selected_handles.is_empty() {
+            let name = state.name.trim();
+            state
+                .existing_names
+                .iter()
+                .find(|existing| existing.eq_ignore_ascii_case(name))
+                .map(|existing| scene.block_preview_wires(existing))
+                .unwrap_or_default()
+        } else {
+            state.empty_prompt = false;
+            let entities: Vec<_> = state
+                .selected_handles
+                .iter()
+                .filter_map(|handle| scene.document.get_entity(*handle).cloned())
+                .collect();
+            scene.wires_for_entities(&entities)
+        };
+    }
+
     pub(super) fn dispatch_blocks(&mut self, cmd: &str, i: usize) -> Option<Task<Message>> {
         match cmd {
             // ── BASE — drawing insertion base point ───────────────────────
@@ -469,6 +499,7 @@ impl OpenCADStudio {
                     ),
                 );
                 self.active_modal = Some(crate::app::ModalKind::BlockDefinition);
+                self.refresh_block_definition_preview();
             }
 
             cmd if cmd.starts_with("BLOCK_POINT_PICKED ") => {
@@ -504,6 +535,7 @@ impl OpenCADStudio {
                 }
                 self.tabs[i].active_cmd = None;
                 self.active_modal = Some(crate::app::ModalKind::BlockDefinition);
+                self.refresh_block_definition_preview();
             }
 
             cmd if cmd.starts_with("WBLOCK_POINT_PICKED ") => {