[refactor] Migrate litegraph imports from npm package to local subtree

- Updated all imports from '@comfyorg/litegraph' to '@/lib/litegraph/src/'
- Replaced deep dist imports with direct source paths
- Updated CSS import in main.ts
- All imports now use the @ alias consistently

src/extensions/core/groupNode.ts

@@ -1,13 +1,12 @@
+import { t } from '@/i18n'
+import { type NodeId } from '@/lib/litegraph/src/LGraphNode'
 import {
   type ExecutableLGraphNode,
   type ExecutionId,
   LGraphNode,
   LiteGraph,
   SubgraphNode
-} from '@comfyorg/litegraph'
-import { type NodeId } from '@comfyorg/litegraph/dist/LGraphNode'
-
-import { t } from '@/i18n'
+} from '@/lib/litegraph/src/litegraph'
 import {
   ComfyLink,
   ComfyNode,