Fix blank GitHub Pages by adding standalone entry point and fixing asset path

The app was blank because: (1) publicPath pointed to /scriptflow/ but Pages
serves from root, and (2) the Canva-only entry point never called render()
outside the Canva framework. Added a standalone ghpages entry point that
mounts the App directly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: manzaro1

canva-app/src/index.ghpages.tsx

@@ -0,0 +1,8 @@
+import React from "react";
+import { createRoot } from "react-dom/client";
+import { App } from "./intents/design_editor/app";
+
+const root = document.getElementById("root");
+if (root) {
+  createRoot(root).render(<App />);
+}

canva-app/webpack.ghpages.config.js

@@ -3,12 +3,12 @@ const webpack = require("webpack");
 const HtmlWebpackPlugin = require("html-webpack-plugin");
 
 module.exports = {
-  entry: "./src/index.tsx",
+  entry: "./src/index.ghpages.tsx",
   output: {
     filename: "app.js",
     path: path.resolve(__dirname, "dist"),
     clean: true,
-    publicPath: "/scriptflow/",
+    publicPath: "./",
   },
   resolve: {
     extensions: [".tsx", ".ts", ".js", ".jsx"],