feat: enhance environment configuration and CORS handling

- Added `NEXT_PUBLIC_APP_URL` and `NEXT_PUBLIC_CONTACT_EMAIL` to environment variables for frontend configuration.
- Updated CORS logic to support domain-based restrictions with dynamic origin validation.
- Improved frontend image hostname resolution using environment-driven URLs.
- Standardized contact email usage across the application.

frontend/next.config.ts

@@ -1,5 +1,16 @@
 import type { NextConfig } from "next";
 
+const appUrl = process.env.NEXT_PUBLIC_APP_URL || "https://memegoat.fr";
+const apiUrl = process.env.NEXT_PUBLIC_API_URL || "https://api.memegoat.fr";
+
+const getHostname = (url: string) => {
+	try {
+		return new URL(url).hostname;
+	} catch {
+		return url;
+	}
+};
+
 const nextConfig: NextConfig = {
 	/* config options here */
 	reactCompiler: true,
@@ -7,11 +18,11 @@ const nextConfig: NextConfig = {
 		remotePatterns: [
 			{
 				protocol: "https",
-				hostname: "memegoat.fr",
+				hostname: getHostname(appUrl),
 			},
 			{
 				protocol: "https",
-				hostname: "api.memegoat.fr",
+				hostname: getHostname(apiUrl),
 			},
 		],
 	},