fix: correct link formatting in README and ensure preview image is displayed

Author: jeffreylanters

README.md

@@ -1,7 +1,9 @@
 # React Unity WebGL Template
 
+![readme preview](https://raw.githubusercontent.com/jeffreylanters/react-unity-webgl-template/main/.github/WIKI/preview.png)
+
 This repository contains a template for integrating Unity WebGL builds into React applications. It provides a seamless way to embed Unity content within React components, allowing developers to leverage the power of both technologies.
 
 This template is designed to be used as a starting point for projects that require Unity WebGL integration, offering a structured setup with essential configurations and workflows. It includes a small example Unity project to demonstrate the integration process.
 
-Check it out at [react-unity-webgl-template](https://template.react-unity-webgl.dev)!
+Check it out at [https://template.react-unity-webgl.dev](https://template.react-unity-webgl.dev)!