[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/useRefreshableSelection.ts

@@ -1,6 +1,6 @@
-import type { LGraphNode } from '@comfyorg/litegraph'
 import { computed, ref, watchEffect } from 'vue'
 
+import type { LGraphNode } from '@/lib/litegraph/src/litegraph'
 import { useCanvasStore } from '@/stores/graphStore'
 import { isLGraphNode } from '@/utils/litegraphUtil'