feat(contribute): upload event images to OneDrive before submission

- ApiClient.uploadFile() — multipart POST to /v1/upload/file (60s timeout)
- ApiEndpoints.uploadFile — points to Node.js upload endpoint
- GamificationService.submitContribution() now uploads each picked image
  to OneDrive via the server upload pipeline, then passes the returned
  { fileId, url, ... } objects as `media` in the submission body
  (replaces broken behaviour of sending local device paths as strings)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/screens/home_screen.dart

@@ -46,6 +46,8 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
   // backend-driven
   List<EventModel> _allEvents = []; // master copy, never filtered
   List<EventModel> _events = [];
+  List<EventModel> _featuredEvents = [];
+  List<EventModel> _topEventsList = [];
   List<EventTypeModel> _types = [];
   int _selectedTypeId = -1; // -1 == All
   bool _categoriesExpanded = false;
@@ -62,6 +64,7 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
     super.initState();
     _heroPageNotifier = ValueNotifier(0);
     _loadUserDataAndEvents();
+    _loadCuratedEvents();
     _startAutoScroll();
     PostHogService.instance.screen('Home');
   }
@@ -112,7 +115,7 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
     _userLng = prefs.getDouble('user_lng');
 
     try {
-      // Fetch types and events in parallel for faster loading.
+      // Fetch types and location-based events in parallel.
       // Prefer haversine (lat/lng) when GPS coords are available; fall back to pincode.
       final results = await Future.wait([
         _events_service_getEventTypesSafe(),
@@ -189,6 +192,24 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
     }
   }
 
+  /// Loads featured carousel + top events once globally — no pincode, never re-fetched on location change.
+  Future<void> _loadCuratedEvents() async {
+    try {
+      final results = await Future.wait([
+        _eventsService.getFeaturedEvents(),
+        _eventsService.getTopEvents(),
+      ]);
+      if (mounted) {
+        setState(() {
+          _featuredEvents = results[0] as List<EventModel>;
+          _topEventsList = results[1] as List<EventModel>;
+        });
+      }
+    } catch (_) {
+      // Non-critical — fallback getters handle empty lists gracefully
+    }
+  }
+
   Future<void> _refresh() async {
     await _loadUserDataAndEvents();
   }
@@ -583,8 +604,51 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
   }
 
 
-  // Get hero events (first 4 events for the carousel)
-  List<EventModel> get _heroEvents => _events.take(6).toList();
+  // Featured events for the hero carousel — from dedicated endpoint, fallback to first 6
+  List<EventModel> get _heroEvents =>
+      _featuredEvents.isNotEmpty ? _featuredEvents : _allEvents.take(6).toList();
+
+  // Top events respecting the active date filter — from dedicated endpoint, fallback to date-filtered all
+  List<EventModel> get _topEventsFiltered {
+    if (_topEventsList.isEmpty) return _allFilteredByDate;
+    if (_selectedDateFilter.isEmpty) return _topEventsList;
+    final now = DateTime.now();
+    final today = DateTime(now.year, now.month, now.day);
+    DateTime filterStart;
+    DateTime filterEnd;
+    switch (_selectedDateFilter) {
+      case 'Today':
+        filterStart = today;
+        filterEnd = today;
+        break;
+      case 'Tomorrow':
+        filterStart = today.add(const Duration(days: 1));
+        filterEnd = filterStart;
+        break;
+      case 'This week':
+        filterStart = today;
+        filterEnd = today.add(Duration(days: 7 - today.weekday));
+        break;
+      case 'Date':
+        if (_selectedCustomDate == null) return _topEventsList;
+        filterStart = DateTime(_selectedCustomDate!.year, _selectedCustomDate!.month, _selectedCustomDate!.day);
+        filterEnd = filterStart;
+        break;
+      default:
+        return _topEventsList;
+    }
+    return _topEventsList.where((e) {
+      try {
+        final s = DateTime.parse(e.startDate);
+        final eEnd = DateTime.parse(e.endDate);
+        final eStart = DateTime(s.year, s.month, s.day);
+        final eEndDay = DateTime(eEnd.year, eEnd.month, eEnd.day);
+        return !eEndDay.isBefore(filterStart) && !eStart.isAfter(filterEnd);
+      } catch (_) {
+        return false;
+      }
+    }).toList();
+  }
 
   String _formatDate(String dateStr) {
     try {
@@ -1641,12 +1705,12 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
           const SizedBox(height: 16),
           SizedBox(
             height: 200,
-            child: _allFilteredByDate.isEmpty && _loading
+            child: _topEventsFiltered.isEmpty && _loading
                 ? SingleChildScrollView(
                     scrollDirection: Axis.horizontal,
                     child: Row(children: List.generate(3, (_) => const Padding(padding: EdgeInsets.only(right: 12), child: EventCardSkeleton()))),
                   )
-                : _allFilteredByDate.isEmpty
+                : _topEventsFiltered.isEmpty
                     ? Center(child: Text(
                         _selectedDateFilter.isNotEmpty ? 'No events for "$_selectedDateFilter"' : 'No events found',
                         style: const TextStyle(color: Color(0xFF9CA3AF)),
@@ -1654,10 +1718,10 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
                     : PageView.builder(
                         controller: PageController(viewportFraction: 0.85),
                         physics: const PageScrollPhysics(),
-                        itemCount: _allFilteredByDate.length,
+                        itemCount: _topEventsFiltered.length,
                         itemBuilder: (context, index) => Padding(
                           padding: const EdgeInsets.only(right: 12),
-                          child: _buildTopEventCard(_allFilteredByDate[index]),
+                          child: _buildTopEventCard(_topEventsFiltered[index]),
                         ),
                       ),
           ),