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/learn_more_screen.dart

@@ -15,7 +15,8 @@ import '../core/constants.dart';
 
 class LearnMoreScreen extends StatefulWidget {
   final int eventId;
-  const LearnMoreScreen({Key? key, required this.eventId}) : super(key: key);
+  final EventModel? initialEvent;
+  const LearnMoreScreen({Key? key, required this.eventId, this.initialEvent}) : super(key: key);
 
   @override
   State<LearnMoreScreen> createState() => _LearnMoreScreenState();
@@ -48,7 +49,13 @@ class _LearnMoreScreenState extends State<LearnMoreScreen> {
   void initState() {
     super.initState();
     _pageNotifier = ValueNotifier(0);
-    _loadEvent();
+    if (widget.initialEvent != null) {
+      _event = widget.initialEvent;
+      _loading = false;
+      WidgetsBinding.instance.addPostFrameCallback((_) => _startAutoScroll());
+    } else {
+      _loadEvent();
+    }
   }
 
   @override