feat: 처방 사용량 페이지에 약품 위치 표시

- rx-usage API에 CD_item_position.CD_NM_sale 조인 추가
- 제품코드 옆에 위치 배지 표시 (📍A-1 형태)
- 인디고 색상 작은 배지로 UI 해치지 않게

backend/app.py

@@ -4085,7 +4085,7 @@ def api_rx_usage():
         
         mssql_session = db_manager.get_session('PM_PRES')
         
-        # 전문의약품 품목별 사용량 집계 쿼리 (현재고: IM_total.IM_QT_sale_debit)
+        # 전문의약품 품목별 사용량 집계 쿼리 (현재고: IM_total.IM_QT_sale_debit, 위치: CD_item_position.CD_NM_sale)
         rx_query = text("""
             SELECT 
                 P.DrugCode as drug_code,
@@ -4096,13 +4096,15 @@ def api_rx_usage():
                 SUM(ISNULL(P.DRUPRICE, 0) * ISNULL(P.QUAN, 1) * ISNULL(P.Days, 1)) as total_amount,
                 COUNT(DISTINCT P.PreSerial) as prescription_count,
                 COALESCE(NULLIF(G.BARCODE, ''), '') as barcode,
-                ISNULL(IT.IM_QT_sale_debit, 0) as current_stock
+                ISNULL(IT.IM_QT_sale_debit, 0) as current_stock,
+                ISNULL(POS.CD_NM_sale, '') as location
             FROM PS_sub_pharm P
             LEFT JOIN PM_DRUG.dbo.CD_GOODS G ON P.DrugCode = G.DrugCode
             LEFT JOIN PM_DRUG.dbo.IM_total IT ON P.DrugCode = IT.DrugCode
+            LEFT JOIN PM_DRUG.dbo.CD_item_position POS ON P.DrugCode = POS.DrugCode
             WHERE P.Indate >= :start_date
               AND P.Indate <= :end_date
-            GROUP BY P.DrugCode, G.GoodsName, G.SplName, G.BARCODE, IT.IM_QT_sale_debit
+            GROUP BY P.DrugCode, G.GoodsName, G.SplName, G.BARCODE, IT.IM_QT_sale_debit, POS.CD_NM_sale
             ORDER BY SUM(ISNULL(P.QUAN, 1) * ISNULL(P.Days, 1)) DESC
         """)
         
@@ -4143,6 +4145,7 @@ def api_rx_usage():
                 'total_amount': int(amount),
                 'prescription_count': rx_count,
                 'current_stock': int(row.current_stock or 0),  # 현재고
+                'location': row.location or '',  # 약국 내 위치
                 'thumbnail': None
             })