Refactor: rename BottomNavigation and update TendersScreen structure

- Renamed BottomNavigation to TenderBottomNavigation for clarity.
- Updated TendersScreen to use TenderBottomNavigation.
- Converted TendersScreen from StatelessWidget to StatefulWidget to manage tab state.
- Added TabController for handling tab changes and improved layout with SafeArea and PageView.

lib/views/home/home_screen.dart

@@ -13,7 +13,7 @@ class Homescreen extends StatelessWidget {
     return Scaffold(
       backgroundColor: Colors.white,
       body: _body(),
-      bottomNavigationBar: BottomNavigation(),
+      bottomNavigationBar: TenderBottomNavigation(),
     );
   }