[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/extensions/core/rerouteNode.ts

@@ -1,5 +1,9 @@
-import type { IContextMenuValue } from '@comfyorg/litegraph'
-import { LGraphCanvas, LGraphNode, LiteGraph } from '@comfyorg/litegraph'
+import type { IContextMenuValue } from '@/lib/litegraph/src/litegraph'
+import {
+  LGraphCanvas,
+  LGraphNode,
+  LiteGraph
+} from '@/lib/litegraph/src/litegraph'
 
 import { app } from '../../scripts/app'
 import { getWidgetConfig, mergeIfValid, setWidgetConfig } from './widgetInputs'