feat: Phase 2 — 11 high-priority gaps implemented across home, auth, gamification, profile, and event detail

Phase 2 gaps completed:
- HOME-001: Hero slider pause-on-touch (GestureDetector wraps PageView)
- HOME-003: Calendar bottom sheet with TableCalendar (replaces custom dialog)
- AUTH-004: District dropdown on signup (14 Kerala districts)
- EVT-003: Mobile sticky "Book Now" bar + desktop CTA wired to CheckoutScreen
- ACH-001: Real achievements from dashboard API with fallback defaults
- GAM-002: 3-card EP row (Lifetime EP / Liquid EP / Reward Points)
- GAM-005: Horizontal tier roadmap Bronze→Silver→Gold→Platinum→Diamond
- CTR-001: Submission status chips (PENDING/APPROVED/REJECTED)
- CTR-002: +EP badge on approved submissions
- PROF-003: Gamification cards on profile screen with Consumer<GamificationProvider>
- UX-001: Shimmer skeleton loaders (shimmer ^3.0.0) replacing CircularProgressIndicator

Already complete (verified, no changes needed):
- HOME-002: Category shelves already built in _buildTypeSection()
- LDR-002: Podium visualization already built (_buildPodium / _buildDesktopPodium)
- BOOK-004: UPI handled natively by Razorpay SDK

Deferred: LOC-001/002 (needs Django haversine endpoint)
Skipped: AUTH-002 (OTP needs SMS provider decision)

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

lib/screens/learn_more_screen.dart

@@ -15,6 +15,7 @@ import '../core/auth/auth_guard.dart';
 import '../core/utils/error_utils.dart';
 import '../core/constants.dart';
 import '../features/reviews/widgets/review_section.dart';
+import 'checkout_screen.dart';
 
 class LearnMoreScreen extends StatefulWidget {
   final int eventId;
@@ -28,6 +29,18 @@ class LearnMoreScreen extends StatefulWidget {
 class _LearnMoreScreenState extends State<LearnMoreScreen> {
   final EventsService _service = EventsService();
 
+  void _navigateToCheckout() {
+    if (!AuthGuard.requireLogin(context, reason: 'Sign in to book this event.')) return;
+    if (_event == null) return;
+    Navigator.of(context).push(MaterialPageRoute(
+      builder: (_) => CheckoutScreen(
+        eventId: _event!.id,
+        eventName: _event!.name,
+        eventImage: _event!.thumbImg,
+      ),
+    ));
+  }
+
   bool _loading = true;
   EventModel? _event;
   String? _error;
@@ -388,9 +401,7 @@ class _LearnMoreScreenState extends State<LearnMoreScreen> {
                       right: 32,
                       bottom: 36,
                       child: ElevatedButton(
-                        onPressed: () {
-                          // TODO: implement booking action
-                        },
+                        onPressed: _navigateToCheckout,
                         style: ElevatedButton.styleFrom(
                           backgroundColor: const Color(0xFF1A56DB),
                           foregroundColor: Colors.white,
@@ -530,6 +541,42 @@ class _LearnMoreScreenState extends State<LearnMoreScreen> {
     // ── MOBILE layout ─────────────────────────────────────────────────────
     return Scaffold(
       backgroundColor: theme.scaffoldBackgroundColor,
+      bottomNavigationBar: (_event != null && _event!.isBookable)
+          ? Container(
+              decoration: BoxDecoration(
+                color: theme.scaffoldBackgroundColor,
+                boxShadow: [
+                  BoxShadow(
+                    color: Colors.black.withOpacity(0.08),
+                    blurRadius: 12,
+                    offset: const Offset(0, -4),
+                  ),
+                ],
+              ),
+              padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
+              child: SafeArea(
+                top: false,
+                child: SizedBox(
+                  height: 52,
+                  child: ElevatedButton(
+                    onPressed: _navigateToCheckout,
+                    style: ElevatedButton.styleFrom(
+                      backgroundColor: const Color(0xFF1A56DB),
+                      foregroundColor: Colors.white,
+                      shape: RoundedRectangleBorder(
+                        borderRadius: BorderRadius.circular(14),
+                      ),
+                      elevation: 0,
+                    ),
+                    child: const Text(
+                      'Book Now',
+                      style: TextStyle(fontSize: 16, fontWeight: FontWeight.w700),
+                    ),
+                  ),
+                ),
+              ),
+            )
+          : null,
       body: Stack(
         children: [
           // ── Scrollable content (carousel + card scroll together) ──