[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/composables/nodePack/useWorkflowPacks.ts

@@ -1,7 +1,7 @@
-import { LGraphNode } from '@comfyorg/litegraph'
 import { computed, onUnmounted, ref } from 'vue'
 
 import { useNodePacks } from '@/composables/nodePack/useNodePacks'
+import { LGraphNode } from '@/lib/litegraph/src/litegraph'
 import { ComfyWorkflowJSON } from '@/schemas/comfyWorkflowSchema'
 import { app } from '@/scripts/app'
 import { useComfyRegistryStore } from '@/stores/comfyRegistryStore'