Add product price retrieval feature in cities

- Implemented a new endpoint in FalukantController to fetch product prices in various cities based on product ID and current price.
- Developed the corresponding service method in FalukantService to calculate and return prices, considering user knowledge and city branches.
- Updated frontend components (RevenueSection and SaleSection) to display better prices for products, including loading logic and UI enhancements for price visibility.
- Added styling for price indicators based on branch types to improve user experience.

backend/routers/falukantRouter.js

@@ -70,6 +70,7 @@ router.post('/politics/elections', falukantController.vote);
 router.get('/politics/open', falukantController.getOpenPolitics);
 router.post('/politics/open', falukantController.applyForElections);
 router.get('/cities', falukantController.getRegions);
+router.get('/products/prices-in-cities', falukantController.getProductPricesInCities);
 router.get('/vehicles/types', falukantController.getVehicleTypes);
 router.post('/vehicles', falukantController.buyVehicles);
 router.get('/vehicles', falukantController.getVehicles);