feat: 판매내역 페이지에 제품 썸네일 이미지 표시

- app.py: /api/sales-detail에서 product_images.db 조회하여 thumbnail 반환
- admin_sales_pos.html: 거래별/목록 뷰에 36x36 썸네일 표시
- 이미지 없는 제품은 📦 플레이스홀더 표시
- barcode 우선, drug_code 폴백으로 이미지 매칭

backend/app.py

@@ -3555,7 +3555,8 @@ def api_sales_detail():
                 'supplier': row.supplier or '',
                 'quantity': quantity,
                 'unit_price': int(unit_price),
-                'total_price': int(total_price)
+                'total_price': int(total_price),
+                'thumbnail': None  # 나중에 채워짐
             })
             
             total_amount += total_price
@@ -3563,9 +3564,57 @@ def api_sales_detail():
                 barcode_count += 1
             unique_products.add(drug_code)
         
+        # 제품 이미지 조회 (product_images.db에서)
+        try:
+            images_db_path = Path(__file__).parent / 'db' / 'product_images.db'
+            if images_db_path.exists():
+                img_conn = sqlite3.connect(str(images_db_path))
+                img_cursor = img_conn.cursor()
+                
+                # barcode와 drug_code 수집
+                barcodes = [item['barcode'] for item in items if item['barcode']]
+                drug_codes = [item['drug_code'] for item in items if item['drug_code']]
+                
+                # 이미지 조회 (barcode 또는 drug_code로 매칭)
+                image_map = {}
+                if barcodes:
+                    placeholders = ','.join(['?' for _ in barcodes])
+                    img_cursor.execute(f'''
+                        SELECT barcode, thumbnail_base64 
+                        FROM product_images 
+                        WHERE barcode IN ({placeholders}) AND thumbnail_base64 IS NOT NULL
+                    ''', barcodes)
+                    for row in img_cursor.fetchall():
+                        image_map[f'bc:{row[0]}'] = row[1]
+                
+                if drug_codes:
+                    placeholders = ','.join(['?' for _ in drug_codes])
+                    img_cursor.execute(f'''
+                        SELECT drug_code, thumbnail_base64 
+                        FROM product_images 
+                        WHERE drug_code IN ({placeholders}) AND thumbnail_base64 IS NOT NULL
+                    ''', drug_codes)
+                    for row in img_cursor.fetchall():
+                        if f'dc:{row[0]}' not in image_map:  # barcode 우선
+                            image_map[f'dc:{row[0]}'] = row[1]
+                
+                img_conn.close()
+                
+                # 아이템에 썸네일 매핑
+                for item in items:
+                    thumb = image_map.get(f'bc:{item["barcode"]}') or image_map.get(f'dc:{item["drug_code"]}')
+                    if thumb:
+                        item['thumbnail'] = thumb
+        except Exception as img_err:
+            logging.warning(f"제품 이미지 조회 오류: {img_err}")
+        
         # 바코드 매핑률 계산
         barcode_rate = round(barcode_count / len(items) * 100, 1) if items else 0
         
+        # 이미지 매핑률 계산
+        image_count = sum(1 for item in items if item.get('thumbnail'))
+        image_rate = round(image_count / len(items) * 100, 1) if items else 0
+        
         return jsonify({
             'success': True,
             'items': items[:500],  # 최대 500건
@@ -3573,6 +3622,7 @@ def api_sales_detail():
                 'total_count': len(items),
                 'total_amount': int(total_amount),
                 'barcode_rate': barcode_rate,
+                'image_rate': image_rate,
                 'unique_products': len(unique_products)
             }
         })