Refactor tenders pagination and enhance API integration

- Updated TendersRepository and TendersService to support cursor-based pagination.
- Modified TendersViewModel to manage pagination state and handle API responses more effectively.
- Replaced existing pagination UI components with a new WindowedPagination widget across desktop, mobile, and tablet views.
- Improved notification handling in the UI to reflect the presence of notifications dynamically.
- Adjusted main tenders slider to ensure proper rendering based on the current page index.

lib/main.dart

@@ -2,6 +2,7 @@
 import 'dart:ui';
 
 import 'package:firebase_messaging/firebase_messaging.dart';
+import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
@@ -130,6 +131,9 @@ class _MyAppState extends State<MyApp> {
   Widget build(BuildContext context) {
     // Listen to theme changes
     final themeProvider = context.watch<ThemeProvider>();
+    final pageTransition = kIsWeb
+        ? const FadeUpwardsPageTransitionsBuilder()
+        : const CupertinoPageTransitionsBuilder();
 
     return ToastificationWrapper(
       child: MaterialApp.router(
@@ -147,10 +151,7 @@ class _MyAppState extends State<MyApp> {
           pageTransitionsTheme: PageTransitionsTheme(
             builders: {
               for (final platform in TargetPlatform.values)
-                platform:
-                    kIsWeb
-                        ? const FadeUpwardsPageTransitionsBuilder()
-                        : const CupertinoPageTransitionsBuilder(),
+                platform: pageTransition,
             },
           ),
           brightness: