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)

resources/css/app.css

@@ -119,6 +119,30 @@
   font-display: swap;
 }
 
+html {
+  background-color: oklch(1 0 0);
+}
+
+html.dark {
+  background-color: oklch(0.145 0 0);
+}
+
+@keyframes aurora {
+  0%,
+  100% {
+    background-position: 0% 50%;
+  }
+  50% {
+    background-position: 100% 50%;
+  }
+}
+
+.bg-aurora {
+  background: linear-gradient(-45deg, #ee7752, #e73c7e, #23a6d5, #23d5ab);
+  background-size: 400% 400%;
+  animation: aurora 15s ease infinite;
+}
+
 /* Basic typography styling for rendered markdown (prose) without Tailwind plugin */
 .prose {
   color: rgb(55 65 81);