[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/executionStore.ts

@@ -1,10 +1,10 @@
-import type { LGraph, Subgraph } from '@comfyorg/litegraph'
 import { defineStore } from 'pinia'
 import { computed, ref } from 'vue'
 
 import type ChatHistoryWidget from '@/components/graph/widgets/ChatHistoryWidget.vue'
 import { useNodeChatHistory } from '@/composables/node/useNodeChatHistory'
 import { useNodeProgressText } from '@/composables/node/useNodeProgressText'
+import type { LGraph, Subgraph } from '@/lib/litegraph/src/litegraph'
 import type {
   DisplayComponentWsMessage,
   ExecutedWsMessage,