Add smart model fallback for out-of-stock products

- When searching for a generic product (e.g., "marlin 4"), show newer models with stock
- Prioritize models by year/generation (2026/GEN 3 > 2025/GEN 2 > 2024/GEN)
- If older model is out of stock, automatically suggest the newer available model
- Example: "marlin 4" now shows MARLIN 4 GEN 3 (2026) when original is out of stock

This ensures customers always see available products instead of "out of stock" messages

🤖 Generated with [Claude Code](https://claude.ai/code)

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

combined_api_search.py

@@ -376,6 +376,57 @@ def get_warehouse_stock_combined_api(query):
     if not results:
         return ["Ürün bulunamadı"]
     
+    # Akıllı model geçişi - eski model stokta yoksa yeni modeli öner
+    # Örn: "marlin 4" arandığında MARLIN 4 yoksa MARLIN 4 GEN 3'ü göster
+    query_normalized = normalize_turkish(query.upper())
+    
+    # Genel ürün adı aranıyorsa (model numarası yok)
+    if not any(year in query_normalized for year in ['GEN', '2024', '2025', '2026', '(20']):
+        # Stokta olan modelleri kontrol et
+        stocked_alternatives = []
+        
+        for product in results:
+            name_normalized = normalize_turkish(product['name'].upper())
+            # Ana ürün adıyla eşleşiyor mu?
+            if query_normalized in name_normalized:
+                # Ana ürün mü?
+                if is_main_product(product['name']):
+                    # Stokta mı veya varyantları var mı?
+                    if product['stock_found'] and product['total_stock'] > 0:
+                        stocked_alternatives.append(product)
+                    else:
+                        # Ana ürün stokta yok, varyantları kontrol et
+                        has_stocked_variants = False
+                        for variant in results:
+                            if (product['name'].upper() in variant['name'].upper() and
+                                variant['stock_found'] and 
+                                variant['total_stock'] > 0 and
+                                not is_main_product(variant['name'])):
+                                has_stocked_variants = True
+                                break
+                        if has_stocked_variants:
+                            stocked_alternatives.append(product)
+        
+        # Eğer alternatifler varsa, en yenisini seç (genelde GEN 3, 2026 vs.)
+        if stocked_alternatives:
+            # Model yılı/versiyonu olanları öncelikle
+            def get_model_priority(product):
+                name = product['name'].upper()
+                if '2026' in name or 'GEN 3' in name:
+                    return 3
+                elif '2025' in name or 'GEN 2' in name:
+                    return 2
+                elif '2024' in name or 'GEN' in name:
+                    return 1
+                else:
+                    return 0
+            
+            stocked_alternatives.sort(key=lambda x: get_model_priority(x), reverse=True)
+            
+            # En yeni modeli öncelikle kullan
+            if stocked_alternatives:
+                results = [stocked_alternatives[0]] + [r for r in results if r != stocked_alternatives[0]]
+    
     # Önce ana ürünleri filtrele
     main_products = []
     variant_products = []