[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/utils/executionUtil.ts

@@ -2,13 +2,12 @@ import type {
   ExecutableLGraphNode,
   ExecutionId,
   LGraph
-} from '@comfyorg/litegraph'
+} from '@/lib/litegraph/src/litegraph'
 import {
   ExecutableNodeDTO,
   LGraphEventMode,
   SubgraphNode
-} from '@comfyorg/litegraph'
-
+} from '@/lib/litegraph/src/litegraph'
 import type {
   ComfyApiWorkflow,
   ComfyWorkflowJSON