fix(blocks): one block definition service for delete, rename and purge on every path

new src/scene/block_service.rs (references, delete, rename, purge candidates, name validation, one error type and message). The command-line RENAME, palette Remove, plugin API, control/MCP block_delete and PURGE all use it. Layout, xref, dynamic-block, anonymous and open-in-editor records are protected; PURGE removes an anonymous block only when nothing references it. PROTOCOL CHANGE: control/MCP block_delete refuses a referenced block unless force=true (erases referencing INSERTs in one undo step). New REST route DELETE /api/v1/blocks/{name}?force=true. MCP tool digest re-pinned. Undo labels are Delete block X, Rename block X to Y and Purge.

src/app/update/blocks_palette.rs

@@ -491,20 +491,31 @@ impl OpenCADStudio {
                 Tab::Current => {
                     let name = item.name();
                     let i = self.active_tab;
-                    let referenced = self.tabs[i].scene.document.entities().any(|e| {
-                        matches!(e, codec::EntityType::Insert(ins) if ins.block_name.eq_ignore_ascii_case(&name))
-                    });
-                    if referenced {
-                        self.command_line.push_error(&crate::tf!(
-                            "Block \"{name}\" is referenced in the drawing and cannot be removed."
-                        ));
-                    } else {
-                        self.push_undo_snapshot(i, "PURGE");
-                        crate::app::control::erase_block_definition(&mut self.tabs[i].scene, &name);
-                        self.tabs[i].dirty = true;
-                        self.command_line
-                            .push_output(&crate::tf!("Block \"{name}\" removed."));
-                        self.refresh_block_palette();
+                    let open_edits: Vec<codec::Handle> = self.tabs[i]
+                        .block_edits
+                        .iter()
+                        .map(|session| session.br_handle)
+                        .collect();
+                    self.push_undo_snapshot(i, format!("Delete block {name}"));
+                    let outcome = crate::scene::block_service::delete(
+                        &mut self.tabs[i].scene,
+                        &name,
+                        crate::scene::block_service::DeleteOptions {
+                            force: false,
+                            open_edits: &open_edits,
+                        },
+                    );
+                    match outcome {
+                        Ok(_) => {
+                            self.tabs[i].dirty = true;
+                            self.command_line
+                                .push_output(&crate::tf!("Block \"{name}\" removed."));
+                            self.refresh_block_palette();
+                        }
+                        Err(error) => {
+                            self.discard_last_undo_entry(i);
+                            self.command_line.push_error(&error.to_string());
+                        }
                     }
                 }
                 Tab::Recent | Tab::Favorites => {

src/app/update/mod.rs

@@ -93,6 +93,8 @@ fn reorder_insertion_index(from: usize, to: usize, after: bool, len: usize) -> O
     (insertion != from).then_some(insertion)
 }
 
+#[cfg(test)]
+mod block_ops_tests;
 mod blocks_palette;
 mod command;
 mod context_menu;