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/ComfyWidgetNodes.ts

@@ -0,0 +1,103 @@
+import { LiteGraph, type ContextMenuItem, type LGraphNode, type Vector2, LConnectionKind, LLink, LGraphCanvas, type SlotType, TitleMode, type SlotLayout, LGraph, type INodeInputSlot } from "@litegraph-ts/core";
+import ComfyGraphNode from "./ComfyGraphNode";
+import ComboWidget from "$lib/widgets/ComboWidget.svelte";
+import RangeWidget from "$lib/widgets/RangeWidget.svelte";
+import TextWidget from "$lib/widgets/TextWidget.svelte";
+import type { SvelteComponentDev } from "svelte/internal";
+import { ComfyWidgets } from "$lib/widgets";
+
+export interface ComfyWidgetProperties extends Record<string, any> {
+    value: any,
+}
+
+/*
+ * A node that is tied to a UI widget in the frontend. When the frontend's
+ * widget is changed, the value of the first output in the node is updated
+ * in the litegraph instance.
+ */
+export abstract class ComfyWidgetNode extends ComfyGraphNode {
+    abstract properties: ComfyWidgetProperties;
+
+    /** Svelte class for the frontend logic */
+    abstract svelteComponentType: typeof SvelteComponentDev
+    /** Compatible litegraph widget types that can be connected to this node */
+    abstract inputWidgetTypes: string[]
+
+    override isBackendNode = false;
+    override serialize_widgets = true;
+
+    override onExecute() {
+        // Assumption: we will have one output in the inherited class with the
+        // correct type
+        this.setOutputData(0, this.properties.value)
+
+        // TODO send event to linked nodes
+    }
+}
+
+export interface ComfySliderProperties extends ComfyWidgetProperties {
+    value: number
+}
+
+export class ComfySliderNode extends ComfyWidgetNode {
+    override properties: ComfySliderProperties = {
+        value: 0
+    }
+
+    override svelteComponentType = RangeWidget
+    override inputWidgetTypes = ["number", "slider"]
+
+    constructor(name?: string) {
+        super(name)
+        this.addOutput("value", "number");
+    }
+}
+
+LiteGraph.registerNodeType({
+    class: ComfySliderNode,
+    title: "ComfyBox.UI.Slider",
+    desc: "Slider outputting a number value",
+    type: "comfybox/ui/slider"
+})
+
+export interface ComfyComboProperties extends ComfyWidgetProperties {
+    options: string[],
+    value: string
+}
+
+export class ComfyComboNode extends ComfyWidgetNode {
+    override properties: ComfyComboProperties = {
+        options: ["*"],
+        value: "*"
+    }
+
+    override svelteComponentType = ComboWidget
+    override inputWidgetTypes = ["combo", "enum"]
+}
+
+LiteGraph.registerNodeType({
+    class: ComfyComboNode,
+    title: "ComfyBox.UI.Combo",
+    desc: "Combo box outputting a string value",
+    type: "comfybox/ui/combo"
+})
+
+export interface ComfyTextProperties extends ComfyWidgetProperties {
+    value: string
+}
+
+export class ComfyTextNode extends ComfyWidgetNode {
+    override properties: ComfyTextProperties = {
+        value: ""
+    }
+
+    override svelteComponentType = TextWidget
+    override inputWidgetTypes = ["text"]
+}
+
+LiteGraph.registerNodeType({
+    class: ComfyTextNode,
+    title: "ComfyBox.UI.Text",
+    desc: "Textbox outputting a string value",
+    type: "comfybox/ui/text"
+})