fix: allow guests to view event details by passing pre-loaded data

LearnMoreScreen now accepts an optional initialEvent parameter so it
can render immediately from already-loaded data instead of re-fetching
from the event-details API. This fixes the guest-mode flow where the
unauthenticated API call was failing. Also changed getEventDetails to
requiresAuth: true so logged-in users send their token when the API
path is used.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/screens/home_desktop_screen.dart

@@ -55,10 +55,10 @@ class _HomeDesktopScreenState extends State<HomeDesktopScreen> {
         return const SettingsScreen();
       default:
         return _HomeContent(
-          onEventTap: (eventId) {
+          onEventTap: (eventId, event) {
             Navigator.push(
               context,
-              MaterialPageRoute(builder: (_) => LearnMoreScreen(eventId: eventId)),
+              MaterialPageRoute(builder: (_) => LearnMoreScreen(eventId: eventId, initialEvent: event)),
             );
           },
         );
@@ -70,7 +70,7 @@ class _HomeDesktopScreenState extends State<HomeDesktopScreen> {
 // Home content — hero, categories, event grid
 // ---------------------------------------------------------------------------
 class _HomeContent extends StatefulWidget {
-  final void Function(int eventId) onEventTap;
+  final void Function(int eventId, EventModel event) onEventTap;
   const _HomeContent({required this.onEventTap});
 
   @override
@@ -573,7 +573,7 @@ class _HomeContentState extends State<_HomeContent>
                                 child: GestureDetector(
                                   onTap: () {
                                     Navigator.of(ctx).pop();
-                                    widget.onEventTap(event.id);
+                                    widget.onEventTap(event.id, event);
                                   },
                                   child: Container(
                                     padding: const EdgeInsets.symmetric(
@@ -753,7 +753,7 @@ class _HomeContentState extends State<_HomeContent>
     return MouseRegion(
       cursor: SystemMouseCursors.click,
       child: GestureDetector(
-        onTap: () => widget.onEventTap(e.id),
+        onTap: () => widget.onEventTap(e.id, e),
         child: Container(
           decoration: BoxDecoration(
             color: Colors.white,