Fix tenant event form package selector so it no longer renders empty-value options, handles loading/empty

states, and pulls data from the authenticated /api/v1/tenant/packages endpoint.
    (resources/js/admin/pages/EventFormPage.tsx, resources/js/admin/api.ts)
  - Harden tenant-admin auth flow: prevent PKCE state loss, scope out StrictMode double-processing, add SPA
    routes for /event-admin/login and /event-admin/logout, and tighten token/session clearing semantics (resources/js/admin/auth/{context,tokens}.tsx, resources/js/admin/pages/{AuthCallbackPage,LogoutPage}.tsx,
    resources/js/admin/router.tsx, routes/web.php)

public/lang/en/marketing.json

@@ -180,7 +180,8 @@
     "message": "Message",
     "sending": "Sending...",
     "send": "Send",
-    "back_home": "Back to Home"
+    "back_home": "Back to Home",
+    "success": "Thanks! We will get back to you soon."
   },
   "occasions": {
     "title": "Fotospiel for :type",