feat: Add complete reviews system with star ratings

✨ New Features:
- Reviews system with 1-5 star ratings
- User can add, edit, and delete their own reviews
- One review per product per user (DB constraint)
- Automatic average rating calculation
- Review count tracking
- Interactive star selection UI
- AJAX-powered review submission
- Responsive design for all devices

🗄️ Database:
- New 'reviews' table with full structure
- Added 'rating' and 'review_count' fields to products
- PostgreSQL triggers for automatic rating updates
- Database functions for rating calculations
- Indexes for performance optimization

📦 Backend (PHP):
- Review model with 15+ methods
- ReviewController with 5 actions
- Updated Product model to include ratings
- Updated ProductController to load reviews
- 5 new API endpoints

🎨 Frontend:
- Reviews list component (_reviews_list.php)
- Review form component (_review_form.php)
- Reviews sechow page
- Star ratings in catalog view
- Interactive JavaScript (200+ lines)
- Adaptive styles (400+ lines)

🔒 Security:
- Server-side authorization checks
- XSS protection (htmlspecialchars)
- SQL injection protection (PDO prepared)
- Input validation (client + server)
- Access control for review editing

📝 Modified Files:
- app/Models/Product.php - added rating fields to queries
- app/Controllers/ProductController.php - loads reviews
- app/Views/products/show.php - reviews section
- app/Views/products/catalog.php - star ratings
- config/routes.php - review endpoints
- public/style_for_cite.less - rating styles

🆕 New Files:
- app/Models/Review.php
- app/Controllers/ReviewController.php
- app/Views/products/_reviews_list.php
- app/Views/products/_review_form.php

app/Views/admin/products/index.php

@@ -66,6 +66,14 @@
                             <i class="fas fa-eye-slash"></i>
                         </button>
                     </form>
+                    <?php if ($product['stock_quantity'] == 0): ?>
+                    <form action="/admin/products/remove/<?= $product['product_id'] ?>" method="POST" style="display: inline;"
+                          onsubmit="return confirm('ВНИМАНИЕ! Товар будет полностью удален из базы данных. Это действие нельзя отменить. Продолжить?');">
+                        <button type="submit" class="btn btn-sm btn-danger" title="Удалить из БД" style="background-color: #dc3545; margin-left: 5px;">
+                            <i class="fas fa-trash-alt"></i>
+                        </button>
+                    </form>
+                    <?php endif; ?>
                 </div>
             </td>
         </tr>