feat: Phase 3 — 26 medium-priority gaps implemented

P3-A/K  Profile: Eventify ID glassmorphic badge (tap-to-copy), DiceBear
        Notionists avatar via TierAvatarRing, district picker (14 pills)
        with 183-day cooldown lock, multipart photo upload to server
P3-B    Home: Top Events converted to PageView scroll-snap
        (viewportFraction 0.9 + PageScrollPhysics)
P3-C    Event detail: contributor widget (tier ring + name + navigation),
        related events horizontal row; added getEventsByCategory() to
        EventsService; added contributorId/Name/Tier fields to EventModel
P3-D    Kerala pincodes: 463-entry JSON (all 14 districts), registered as
        asset, async-loaded in SearchScreen replacing hardcoded 32 cities
P3-E    Checkout: promo code field + Apply/Remove button in Step 2,
        discountAmount subtracted from total, applyPromo()/resetPromo()
        methods in CheckoutProvider
P3-F/G  Gamification: reward cycle countdown + EP→RP progress bar (blue→
        amber) in contribute + profile screens; TierAvatarRing in podium
        and all leaderboard rows; GlassCard current-user stats card at
        top of leaderboard tab
P3-H    New ContributorProfileScreen: tier ring, stats, submission grid
        with status chips; getDashboardForUser() in GamificationService;
        wired from leaderboard row taps
P3-I    Achievements: 11 default badges (up from 6), 6 new icon map
        entries; progress % labels already confirmed present
P3-J    Reviews: CustomPainter circular arc rating ring (amber, 84px)
        replaces large rating number in ReviewSummary
P3-L    Share rank card: RepaintBoundary → PNG capture → Share.shareXFiles;
        share button wired in profile header and leaderboard tab
P3-M    SafeArea audit: home bottom nav, contribute/achievements scroll
        padding, profile CustomScrollView top inset

New files: tier_avatar_ring.dart, glass_card.dart,
  eventify_bottom_sheet.dart, contributor_profile_screen.dart,
  share_rank_card.dart, assets/data/kerala_pincodes.json
New dep:   path_provider ^2.1.0

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

lib/screens/home_screen.dart

@@ -50,7 +50,7 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
   bool _loading = true;
 
   // Hero carousel
-  final PageController _heroPageController = PageController(viewportFraction: 0.88);
+  final PageController _heroPageController = PageController(viewportFraction: 0.9);
   late final ValueNotifier<int> _heroPageNotifier;
   Timer? _autoScrollTimer;
 
@@ -453,10 +453,11 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
           ),
 
           // Floating bottom navigation (always visible)
+          // bottom offset accounts for home indicator on iPhone/Android gesture bar
           Positioned(
             left: 16,
             right: 16,
-            bottom: 16,
+            bottom: MediaQuery.of(context).padding.bottom + 16,
             child: _buildFloatingBottomNav(),
           ),
         ],
@@ -1532,11 +1533,14 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
                         _selectedDateFilter.isNotEmpty ? 'No events for "$_selectedDateFilter"' : 'No events found',
                         style: const TextStyle(color: Color(0xFF9CA3AF)),
                       ))
-                    : ListView.separated(
-                        scrollDirection: Axis.horizontal,
+                    : PageView.builder(
+                        controller: PageController(viewportFraction: 0.85),
+                        physics: const PageScrollPhysics(),
                         itemCount: _allFilteredByDate.length,
-                        separatorBuilder: (_, __) => const SizedBox(width: 12),
-                        itemBuilder: (context, index) => _buildTopEventCard(_allFilteredByDate[index]),
+                        itemBuilder: (context, index) => Padding(
+                          padding: const EdgeInsets.only(right: 12),
+                          child: _buildTopEventCard(_allFilteredByDate[index]),
+                        ),
                       ),
           ),
           const SizedBox(height: 24),