[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/graph/GraphCanvasMenu.vue

@@ -70,13 +70,13 @@
 </template>
 
 <script setup lang="ts">
-import { LiteGraph } from '@comfyorg/litegraph'
 import Button from 'primevue/button'
 import ButtonGroup from 'primevue/buttongroup'
 import { computed } from 'vue'
 import { useI18n } from 'vue-i18n'
 
 import { useCanvasInteractions } from '@/composables/graph/useCanvasInteractions'
+import { LiteGraph } from '@/lib/litegraph/src/litegraph'
 import { useCommandStore } from '@/stores/commandStore'
 import { useCanvasStore } from '@/stores/graphStore'
 import { useSettingStore } from '@/stores/settingStore'