Subgraph/workflow breadcrumbs menu updates (#7852)

## Summary
For users who don't use subgraphs, the workflow name in the top left can
be unnecessarily obstructive so this updated collapses it to a simple
icon until a subgraph is entered.

## Changes

- Add menu button to WorkflowTab for quick workflow actions
- Add menu and back button to SubgraphBreadcrumb
- Extract shared menu items to useBreadcrumbMenu composable
- Add Comfy.RenameWorkflow command for renaming persisted workflows
- Menu always shows root workflow menu, even when in subgraph

## Screenshots (if applicable)

<img width="399" height="396" alt="image"
src="https://github.com/user-attachments/assets/701ab60e-790f-4d1e-a817-dc42b2d98712"
/>
<img width="569" height="381" alt="image"
src="https://github.com/user-attachments/assets/fcea3ab0-8388-4c72-a649-1428c1defd6a"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7852-Subgraph-workflow-breadcrumbs-menu-updates-2df6d73d3650815b8490ca0a9a92d540)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>
Co-authored-by: GitHub Action <action@github.com>

src/composables/useCoreCommands.ts

@@ -188,6 +188,26 @@ export function useCoreCommands(): ComfyCommand[] {
         await workflowService.saveWorkflowAs(workflow)
       }
     },
+    {
+      id: 'Comfy.RenameWorkflow',
+      icon: 'pi pi-pencil',
+      label: 'Rename Workflow',
+      menubarLabel: 'Rename',
+      function: async () => {
+        const workflow = workflowStore.activeWorkflow
+        if (!workflow || !workflow.isPersisted) return
+
+        const newName = await dialogService.prompt({
+          title: t('g.rename'),
+          message: t('workflowService.enterFilename') + ':',
+          defaultValue: workflow.filename
+        })
+        if (!newName || newName === workflow.filename) return
+
+        const newPath = workflow.directory + '/' + newName + '.json'
+        await workflowService.renameWorkflow(workflow, newPath)
+      }
+    },
     {
       id: 'Comfy.ExportWorkflow',
       icon: 'pi pi-download',