Enhance meta tags and add robots.txt

Updated meta tags in +layout.svelte for improved SEO and social sharing, including more detailed Twitter and Open Graph tags. Added robots.txt to control crawler access and reference sitemap.

Author: gary149

src/routes/+layout.svelte

@@ -182,19 +182,28 @@
 </script>
 
 <svelte:head>
-	<title>{publicConfig.PUBLIC_APP_NAME}</title>
+	<title>{publicConfig.PUBLIC_APP_NAME} - Chat with AI models</title>
 	<meta name="description" content={publicConfig.PUBLIC_APP_DESCRIPTION} />
 	<meta name="twitter:card" content="summary_large_image" />
 	<meta name="twitter:site" content="@huggingface" />
+	<meta name="twitter:title" content="{publicConfig.PUBLIC_APP_NAME} - Chat with AI models" />
+	<meta name="twitter:description" content={publicConfig.PUBLIC_APP_DESCRIPTION} />
+	<meta
+		name="twitter:image"
+		content="{publicConfig.PUBLIC_ORIGIN || page.url.origin}{publicConfig.assetPath}/thumbnail.png"
+	/>
+	<meta name="twitter:image:alt" content="{publicConfig.PUBLIC_APP_NAME} preview" />
 
 	<!-- use those meta tags everywhere except on special listing pages -->
 	<!-- feel free to refacto if there's a better way -->
 	{#if !page.url.pathname.includes("/models/")}
-		<meta property="og:title" content={publicConfig.PUBLIC_APP_NAME} />
+		<meta property="og:title" content="{publicConfig.PUBLIC_APP_NAME} - Chat with AI models" />
 		<meta property="og:type" content="website" />
 		<meta property="og:url" content="{publicConfig.PUBLIC_ORIGIN || page.url.origin}{base}" />
 		<meta property="og:image" content="{publicConfig.assetPath}/thumbnail.png" />
 		<meta property="og:description" content={publicConfig.PUBLIC_APP_DESCRIPTION} />
+		<meta property="og:site_name" content={publicConfig.PUBLIC_APP_NAME} />
+		<meta property="og:locale" content="en_US" />
 	{/if}
 	<link rel="icon" href="{publicConfig.assetPath}/icon.svg" type="image/svg+xml" />
 	{#if publicConfig.PUBLIC_ORIGIN}

static/robots.txt

@@ -0,0 +1,10 @@
+User-agent: *
+Allow: /
+Allow: /r/
+Disallow: /conversation/
+Disallow: /api/
+Disallow: /login
+Disallow: /logout
+
+# Sitemap
+# Sitemap: https://huggingface.co/chat/sitemap.xml