feat(app_configuration): add advertisements configuration tab

- Create new tab for ad settings in App Configuration page
- Implement AdvertisementsConfigurationTab widget
- Add AdConfigForm to handle ad settings input
- Include localization support for tab content

Author: fulleni

lib/app_configuration/view/tabs/advertisements_configuration_tab.dart

@@ -0,0 +1,49 @@
+import 'package:core/core.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_news_app_web_dashboard_full_source_code/app_configuration/widgets/ad_config_form.dart';
+import 'package:flutter_news_app_web_dashboard_full_source_code/l10n/l10n.dart';
+import 'package:ui_kit/ui_kit.dart';
+
+/// {@template advertisements_configuration_tab}
+/// A widget representing the "Advertisements" tab in the App Configuration page.
+///
+/// This tab allows configuration of various ad settings.
+/// {@endtemplate}
+class AdvertisementsConfigurationTab extends StatelessWidget {
+  /// {@macro advertisements_configuration_tab}
+  const AdvertisementsConfigurationTab({
+    required this.remoteConfig,
+    required this.onConfigChanged,
+    super.key,
+  });
+
+  /// The current [RemoteConfig] object.
+  final RemoteConfig remoteConfig;
+
+  /// Callback to notify parent of changes to the [RemoteConfig].
+  final ValueChanged<RemoteConfig> onConfigChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    final l10n = AppLocalizationsX(context).l10n;
+
+    return ListView(
+      padding: const EdgeInsets.all(AppSpacing.lg),
+      children: [
+        // Top-level ExpansionTile for Ad Settings
+        ExpansionTile(
+          title: Text(l10n.adSettingsTitle),
+          childrenPadding: const EdgeInsets.symmetric(
+            horizontal: AppSpacing.xxl,
+          ),
+          children: [
+            AdConfigForm(
+              remoteConfig: remoteConfig,
+              onConfigChanged: onConfigChanged,
+            ),
+          ],
+        ),
+      ],
+    );
+  }
+}