Serialize node links instead of widget values

Syncing litegraph widget state is kinda annoying, and unnecessary since
everything will be moved to separate UI component nodes. Instead I
modified the input slot type to store the min/max/step to be copied into
the default UI node later. Now nothing uses litegraph's widgets anymore

src/lib/nodes/ComfyGraphNode.ts

@@ -1,8 +1,9 @@
 import type ComfyWidget from "$lib/components/widgets/ComfyWidget";
-import { LGraphNode } from "@litegraph-ts/core";
+import { LGraph, LGraphNode } from "@litegraph-ts/core";
 
 export default class ComfyGraphNode extends LGraphNode {
-    isVirtualNode: boolean = false;
+    comfyClass: string | null
+    isBackendNode?: boolean;
 
     afterQueued?(): void;
     onExecuted?(output: any): void;