feat(session): preserve intended URL across session timeout and add expiry warning dialog

When a session expires, the user's current URL is now captured and restored
after re-authentication (via remember-me cookie or manual login), instead of
always redirecting to the dashboard. A JavaScript session warning dialog
appears ~2 minutes before idle timeout, allowing users to extend their session
with a single click. Includes open-redirect prevention via URL validation,
Microsoft SSO callback support, and 33 unit tests.

Refs: SESSION-REDIRECT-PRESERVE-001

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/App/Container/Registrars/AppServicesRegistrar.php

@@ -8,6 +8,7 @@ use MintyPHP\Http\ApiSystemAuditReporter;
 use MintyPHP\Http\CookieStore;
 use MintyPHP\Http\CookieStoreInterface;
 use MintyPHP\Http\Input\RequestInputFactory;
+use MintyPHP\Http\IntendedUrlService;
 use MintyPHP\Http\RequestRuntime;
 use MintyPHP\Http\RequestRuntimeInterface;
 use MintyPHP\Http\SessionStore;
@@ -82,6 +83,7 @@ final class AppServicesRegistrar implements ContainerRegistrar
             $c->get(UserReadRepository::class)
         ));
         $container->set(GridUserCountEnricher::class, static fn (): GridUserCountEnricher => new GridUserCountEnricher());
+        $container->set(IntendedUrlService::class, static fn (): IntendedUrlService => new IntendedUrlService());
         $container->set(RequestInputFactory::class, static fn (): RequestInputFactory => new RequestInputFactory());
         $container->set(SessionStore::class, static fn (): SessionStore => new SessionStore());
         $container->set(SessionStoreInterface::class, static fn (AppContainer $c): SessionStoreInterface => $c->get(SessionStore::class));