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/ComfyReroute.ts

@@ -18,9 +18,6 @@ export default class ComfyReroute extends ComfyGraphNode {
         }
     }
 
-    // This node is purely frontend and does not impact the resulting prompt so should not be serialized
-    override isVirtualNode: boolean = true;
-
     override titleMode: TitleMode = TitleMode.NO_TITLE;
     override collapsable: boolean = false;