Exempt public event registration POST from ladill-link CSRF checks.

Registration forms post to ladl.link first; Events-issued CSRF tokens cannot
validate against the Link app session and caused token mismatch errors.

Co-authored-by: Cursor <cursoragent@cursor.com>

bootstrap/app.php

@@ -13,6 +13,11 @@ return Application::configure(basePath: dirname(__DIR__))
         health: '/up',
     )
     ->withMiddleware(function (Middleware $middleware): void {
+        // Public event registration POSTs land on ladl.link first; CSRF tokens from Events HTML do not match here.
+        $middleware->validateCsrfTokens(except: [
+            '*/register',
+        ]);
+
         $middleware->redirectGuestsTo(fn (Request $request) => route('sso.connect', [
             'redirect' => $request->fullUrl(),
         ]));