[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/stores/nodeDefStore.ts

@@ -1,9 +1,9 @@
-import type { LGraphNode } from '@comfyorg/litegraph'
 import axios from 'axios'
 import _ from 'lodash'
 import { defineStore } from 'pinia'
 import { computed, ref } from 'vue'
 
+import type { LGraphNode } from '@/lib/litegraph/src/litegraph'
 import { transformNodeDefV1ToV2 } from '@/schemas/nodeDef/migration'
 import type {
   ComfyNodeDef as ComfyNodeDefV2,