header metadata for user links

.gitignore

@@ -9,3 +9,4 @@ node_modules
 vite.config.js.timestamp-*
 vite.config.ts.timestamp-*
 service-account.json
+build.zip

src/routes/[username]/+page.svelte

@@ -41,6 +41,7 @@
 <svelte:head>
   <title>@{data.username} Links</title>
   <meta name="description" content="={data.bio}" />
+  <meta name="og:image" content="{data.photoURL}" />
 </svelte:head>
 
 <main class=" prose text-center mx-auto mt-8">