feat: add complete review/rating system for events

New feature: Users can view, submit, and interact with event reviews.

Components added:
- ReviewModel, ReviewStatsModel, ReviewListResponse (models)
- ReviewService with getReviews, submitReview, markHelpful, flagReview
- StarRatingInput (interactive 5-star picker with labels)
- StarDisplay (read-only fractional star display)
- ReviewSummary (average rating + distribution bars)
- ReviewForm (star picker + comment field + submit/update)
- ReviewCard (avatar, timestamp, expandable comment, helpful/flag)
- ReviewSection (main container with pagination and state mgmt)

Integration:
- Added to LearnMoreScreen (both mobile and desktop layouts)
- Review API endpoints point to app.eventifyplus.com Node.js backend
- EventModel updated with averageRating/reviewCount fields

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

lib/features/reviews/widgets/review_summary.dart

@@ -0,0 +1,98 @@
+// lib/features/reviews/widgets/review_summary.dart
+import 'package:flutter/material.dart';
+import '../models/review_models.dart';
+import 'star_display.dart';
+
+class ReviewSummary extends StatelessWidget {
+  final ReviewStatsModel stats;
+
+  const ReviewSummary({Key? key, required this.stats}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    final maxCount = stats.distribution.values.fold<int>(0, (a, b) => a > b ? a : b);
+
+    return Container(
+      padding: const EdgeInsets.all(16),
+      decoration: BoxDecoration(
+        color: Colors.white,
+        borderRadius: BorderRadius.circular(16),
+        boxShadow: [
+          BoxShadow(color: Colors.black.withValues(alpha: 0.06), blurRadius: 12, offset: const Offset(0, 4)),
+        ],
+      ),
+      child: Row(
+        crossAxisAlignment: CrossAxisAlignment.center,
+        children: [
+          // Left: average rating + stars + count
+          Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Text(
+                stats.averageRating.toStringAsFixed(1),
+                style: const TextStyle(
+                  fontSize: 40,
+                  fontWeight: FontWeight.bold,
+                  color: Color(0xFF1E293B),
+                  height: 1.1,
+                ),
+              ),
+              const SizedBox(height: 4),
+              StarDisplay(rating: stats.averageRating, size: 18),
+              const SizedBox(height: 4),
+              Text(
+                '${stats.reviewCount} review${stats.reviewCount == 1 ? '' : 's'}',
+                style: const TextStyle(fontSize: 12, color: Color(0xFF64748B)),
+              ),
+            ],
+          ),
+          const SizedBox(width: 24),
+          // Right: distribution bars
+          Expanded(
+            child: Column(
+              mainAxisSize: MainAxisSize.min,
+              children: List.generate(5, (i) {
+                final star = 5 - i;
+                final count = stats.distribution[star] ?? 0;
+                final fraction = maxCount > 0 ? count / maxCount : 0.0;
+                return Padding(
+                  padding: const EdgeInsets.symmetric(vertical: 2),
+                  child: Row(
+                    children: [
+                      SizedBox(
+                        width: 18,
+                        child: Text('$star', style: const TextStyle(fontSize: 12, fontWeight: FontWeight.w600, color: Color(0xFF64748B))),
+                      ),
+                      const Icon(Icons.star_rounded, size: 12, color: Color(0xFFFBBF24)),
+                      const SizedBox(width: 6),
+                      Expanded(
+                        child: ClipRRect(
+                          borderRadius: BorderRadius.circular(4),
+                          child: AnimatedContainer(
+                            duration: const Duration(milliseconds: 300),
+                            height: 8,
+                            child: LinearProgressIndicator(
+                              value: fraction,
+                              backgroundColor: const Color(0xFFF1F5F9),
+                              valueColor: const AlwaysStoppedAnimation<Color>(Color(0xFFFBBF24)),
+                              minHeight: 8,
+                            ),
+                          ),
+                        ),
+                      ),
+                      const SizedBox(width: 8),
+                      SizedBox(
+                        width: 24,
+                        child: Text('$count', style: const TextStyle(fontSize: 11, color: Color(0xFF94A3B8))),
+                      ),
+                    ],
+                  ),
+                );
+              }),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}