better-route: CORS and preflight

Define an explicit origin policy and attach it before declaring the routes that should inherit it.

use BetterRoute\Middleware\Cors\CorsMiddleware;
use BetterRoute\Middleware\Cors\CorsPolicy;

$cors = new CorsMiddleware(new CorsPolicy(
    allowedOrigins: ['https://app.example.com'],
    allowedMethods: ['GET', 'POST', 'PATCH', 'DELETE', 'OPTIONS'],
    allowCredentials: true,
    maxAgeSeconds: 600,
));

$router->middleware([$cors]);