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/tenders/widgets/tender_app_bar.dart

@@ -0,0 +1,33 @@
+import 'package:flutter/material.dart';
+
+import '../../../core/constants/assets.dart';
+import '../../../core/constants/colors.dart';
+import '../../../core/constants/strings.dart';
+import '../../../core/utils/size_config.dart';
+
+class TenderAppBar extends StatelessWidget {
+  const TenderAppBar({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      mainAxisAlignment: MainAxisAlignment.spaceBetween,
+      children: [
+        Text(
+          AppStrings.tendersTitle,
+          style: TextStyle(
+            fontSize: 20.0.sp(),
+            fontWeight: FontWeight.w600,
+            color: AppColors.grey70,
+          ),
+        ),
+        Image.asset(
+          AssetsManager.tenderLogo,
+          width: 59.0.w(),
+          height: 28.0.h(),
+          fit: BoxFit.cover,
+        ),
+      ],
+    );
+  }
+}