update production domain to stellarsplit-dapp.vercel.app

Replace old splitapp-steel.vercel.app fallback with the new custom
domain in metadataBase, sitemap, and robots config.

Author: Kingsman-99

src/app/layout.tsx

@@ -59,7 +59,7 @@ export const metadata: Metadata = {
     "Create on-chain invoices on Stellar where multiple payers each owe a share. USDC auto-routes to recipients when fully funded.",
   metadataBase: new URL(
     process.env.NEXT_PUBLIC_APP_URL ??
-      (process.env.VERCEL_URL ? `https://${process.env.VERCEL_URL}` : "https://splitapp-steel.vercel.app")
+      (process.env.VERCEL_URL ? `https://${process.env.VERCEL_URL}` : "https://stellarsplit-dapp.vercel.app")
   ),
   manifest: "/manifest.json",
   appleWebApp: {

src/app/robots.ts

@@ -2,7 +2,7 @@ import { MetadataRoute } from "next";
 
 const appUrl =
   process.env.NEXT_PUBLIC_APP_URL ??
-  (process.env.VERCEL_URL ? `https://${process.env.VERCEL_URL}` : "https://splitapp-steel.vercel.app");
+  (process.env.VERCEL_URL ? `https://${process.env.VERCEL_URL}` : "https://stellarsplit-dapp.vercel.app");
 
 export default function robots(): MetadataRoute.Robots {
   return {

src/app/sitemap.ts

@@ -2,7 +2,7 @@ import { MetadataRoute } from "next";
 
 const appUrl =
   process.env.NEXT_PUBLIC_APP_URL ??
-  (process.env.VERCEL_URL ? `https://${process.env.VERCEL_URL}` : "https://splitapp-steel.vercel.app");
+  (process.env.VERCEL_URL ? `https://${process.env.VERCEL_URL}` : "https://stellarsplit-dapp.vercel.app");
 
 export default function sitemap(): MetadataRoute.Sitemap {
   const publicPaths = [