[Subgraph] Add subgraph breadcrumbs component (#3241)

Co-authored-by: filtered <176114999+webfiltered@users.noreply.github.com>

src/utils/typeGuardUtil.ts

@@ -1,4 +1,5 @@
-import { LGraphNode } from '@comfyorg/litegraph'
+import { LGraph, LGraphNode } from '@comfyorg/litegraph'
+import { Subgraph } from '@comfyorg/litegraph'
 
 import type { PrimitiveNode } from '@/extensions/core/widgetInputs'
 
@@ -16,3 +17,7 @@ export const isAbortError = (
   err: unknown
 ): err is DOMException & { name: 'AbortError' } =>
   err instanceof DOMException && err.name === 'AbortError'
+
+export const isSubgraph = (
+  item: LGraph | Subgraph | undefined | null
+): item is Subgraph => item?.isRootGraph === false