chore: Move editor into codebase (#2930)

shared/editor/nodes/Text.ts

@@ -0,0 +1,19 @@
+import { Node as ProsemirrorNode, NodeSpec } from "prosemirror-model";
+import { MarkdownSerializerState } from "../lib/markdown/serializer";
+import Node from "./Node";
+
+export default class Text extends Node {
+  get name() {
+    return "text";
+  }
+
+  get schema(): NodeSpec {
+    return {
+      group: "inline",
+    };
+  }
+
+  toMarkdown(state: MarkdownSerializerState, node: ProsemirrorNode) {
+    state.text(node.text || "", undefined);
+  }
+}