fix: fetch full event details in background to show important information

When navigating from the home screen, LearnMoreScreen now shows the
pre-loaded event data instantly, then silently fetches full details
from the event-details API in the background. This fills in fields
missing from the slim list endpoint (important_information, images,
important_info) without showing a loading spinner.

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

lib/screens/learn_more_screen.dart

@@ -52,7 +52,11 @@ class _LearnMoreScreenState extends State<LearnMoreScreen> {
     if (widget.initialEvent != null) {
       _event = widget.initialEvent;
       _loading = false;
-      WidgetsBinding.instance.addPostFrameCallback((_) => _startAutoScroll());
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        _startAutoScroll();
+        // Fetch full event details in background to get important_information, images, etc.
+        _loadFullDetails();
+      });
     } else {
       _loadEvent();
     }
@@ -71,6 +75,21 @@ class _LearnMoreScreenState extends State<LearnMoreScreen> {
   // Data loading
   // ---------------------------------------------------------------------------
 
+  /// Silently fetch full event details to fill in fields missing from the list
+  /// endpoint (important_information, images, etc.) without showing a loader.
+  Future<void> _loadFullDetails() async {
+    try {
+      final ev = await _service.getEventDetails(widget.eventId);
+      if (!mounted) return;
+      setState(() {
+        _event = ev;
+      });
+      _startAutoScroll();
+    } catch (_) {
+      // Silently fail — the pre-loaded data is already displayed
+    }
+  }
+
   Future<void> _loadEvent() async {
     setState(() {
       _loading = true;