Refactor: reorganize login screen structure and remove unused components

- Updated import path for the login screen.
- Removed the AppStrings class from constants as it has been integrated into core constants.
- Deleted unused files related to the home page and login components, including progress bars, statistics cards, and tenders list items.
- Cleaned up widget imports in the login screen to streamline the codebase.

lib/views/login/widgets/login_button.dart

@@ -0,0 +1,38 @@
+import 'package:flutter/material.dart';
+
+import '../../../core/constants/colors.dart';
+import '../../../core/constants/strings.dart';
+import '../../../size_config.dart';
+
+class LoginButton extends StatelessWidget {
+  final bool isEnabled;
+  final VoidCallback? onPressed;
+
+  const LoginButton({
+    super.key,
+    required this.isEnabled,
+    required this.onPressed,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return SizedBox(
+      width: double.infinity,
+      height: 55.0.h(),
+      child: ElevatedButton(
+        onPressed: onPressed,
+        style: ElevatedButton.styleFrom(
+          backgroundColor: isEnabled ? AppColors.mainBlue : Colors.grey[300],
+          foregroundColor: Colors.white,
+          shape: RoundedRectangleBorder(
+            borderRadius: BorderRadius.circular(28.0.w()),
+          ),
+        ),
+        child: Text(
+          AppStrings.loginButton,
+          style: TextStyle(fontSize: 16.0.sp(), fontWeight: FontWeight.bold),
+        ),
+      ),
+    );
+  }
+}