Bind app sessions to the platform auth session.

Clear local sessions when auth.ladill.com signs out and ping the platform session from keepalive.

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

bootstrap/app.php

@@ -19,6 +19,9 @@ return Application::configure(basePath: dirname(__DIR__))
         $middleware->web(append: [
             \App\Http\Middleware\SetActingAccount::class,
         ]);
+        $middleware->alias([
+            'platform.session' => \App\Http\Middleware\EnsurePlatformSession::class,
+        ]);
 
         // External registrar webhook posts have no CSRF token.
         $middleware->validateCsrfTokens(except: [