[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/components/dialog/content/MissingCoreNodesMessage.vue

@@ -42,11 +42,11 @@
 </template>
 
 <script setup lang="ts">
-import type { LGraphNode } from '@comfyorg/litegraph'
 import { whenever } from '@vueuse/core'
 import Message from 'primevue/message'
 import { computed, ref } from 'vue'
 
+import type { LGraphNode } from '@/lib/litegraph/src/litegraph'
 import { useSystemStatsStore } from '@/stores/systemStatsStore'
 import { compareVersions } from '@/utils/formatUtil'