finish embed components

library/embed/embed-thumbnail.tsx

@@ -0,0 +1,23 @@
+import React from "react"
+import { ReacordElement } from "../element.js"
+import { EmbedChildNode } from "./embed-child.js"
+import type { EmbedOptions } from "./embed-options"
+
+export type EmbedThumbnailProps = {
+  url: string
+}
+
+export function EmbedThumbnail(props: EmbedThumbnailProps) {
+  return (
+    <ReacordElement
+      props={props}
+      createNode={() => new EmbedThumbnailNode(props)}
+    />
+  )
+}
+
+class EmbedThumbnailNode extends EmbedChildNode<EmbedThumbnailProps> {
+  override modifyEmbedOptions(options: EmbedOptions): void {
+    options.thumbnail = { url: this.props.url }
+  }
+}