Simplify site metadata and centralize site configuration

app/layout.tsx

@@ -2,6 +2,7 @@ import type { Metadata } from "next";
 import { Geist, Geist_Mono } from "next/font/google";
 
 import { ThemeProvider } from "@/components/layout/theme-provider";
+import { siteConfig } from "@/lib/site";
 import "./globals.css";
 
 const geistSans = Geist({
@@ -14,47 +15,9 @@ const geistMono = Geist_Mono({
   subsets: ["latin"],
 });
 
-const siteName = "Vertex — The Unified AI Gateway";
-const siteDescription =
-  "Route, optimize, and observe every AI model request through one OpenAI-compatible API.";
-
-// Absolute origin behind `metadataBase`, so Open Graph images resolve to full
-// URLs. Vercel injects VERCEL_PROJECT_PRODUCTION_URL on deployed builds.
-const siteUrl =
-  process.env.NEXT_PUBLIC_SITE_URL ??
-  (process.env.VERCEL_PROJECT_PRODUCTION_URL
-    ? `https://${process.env.VERCEL_PROJECT_PRODUCTION_URL}`
-    : "http://localhost:3000");
-
-// Routes only set their own `title`; the template appends the site name.
 export const metadata: Metadata = {
-  metadataBase: new URL(siteUrl),
-  title: {
-    default: siteName,
-    template: `%s — ${siteName}`,
-  },
-  description: siteDescription,
-  openGraph: {
-    type: "website",
-    siteName,
-    title: siteName,
-    description: siteDescription,
-    url: "/",
-    images: [
-      {
-        url: "/og.png",
-        width: 1732,
-        height: 908,
-        alt: "Vertex — One API for every AI model",
-      },
-    ],
-  },
-  twitter: {
-    card: "summary_large_image",
-    title: siteName,
-    description: siteDescription,
-    images: ["/og.png"],
-  },
+  title: siteConfig.name,
+  description: siteConfig.description,
 };
 
 export default function RootLayout({