feat(app_configuration): add feed configuration tab

- Implement FeedConfigurationTab widget for configuring user content limits and feed decorators
- Add UserPreferenceLimitsForm and FeedDecoratorForm to handle specific configuration tasks
- Include localization support for various feed decorator types
- Ensure responsive layout with appropriate padding and spacing

Author: fulleni

lib/app_configuration/view/tabs/feed_configuration_tab.dart

@@ -0,0 +1,99 @@
+import 'package:core/core.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:flutter_news_app_web_dashboard_full_source_code/app_configuration/bloc/app_configuration_bloc.dart';
+import 'package:flutter_news_app_web_dashboard_full_source_code/app_configuration/widgets/feed_decorator_form.dart';
+import 'package:flutter_news_app_web_dashboard_full_source_code/app_configuration/widgets/user_preference_limits_form.dart';
+import 'package:flutter_news_app_web_dashboard_full_source_code/l10n/l10n.dart';
+import 'package:flutter_news_app_web_dashboard_full_source_code/shared/extensions/feed_decorator_type_l10n.dart';
+import 'package:ui_kit/ui_kit.dart';
+
+/// {@template feed_configuration_tab}
+/// A widget representing the "Feed" tab in the App Configuration page.
+///
+/// This tab allows configuration of user content limits and feed decorators.
+/// {@endtemplate}
+class FeedConfigurationTab extends StatelessWidget {
+  /// {@macro feed_configuration_tab}
+  const FeedConfigurationTab({
+    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 User Content Limits
+        ExpansionTile(
+          title: Text(l10n.userContentLimitsTitle),
+          childrenPadding: const EdgeInsets.symmetric(
+            horizontal: AppSpacing.xxl,
+          ),
+          children: [
+            UserPreferenceLimitsForm(
+              remoteConfig: remoteConfig,
+              onConfigChanged: onConfigChanged,
+            ),
+          ],
+        ),
+        const SizedBox(height: AppSpacing.lg),
+        // Description for Feed Decorators section
+        Text(
+          l10n.feedDecoratorsDescription,
+          style: Theme.of(context).textTheme.bodySmall?.copyWith(
+            color: Theme.of(context).colorScheme.onSurface.withOpacity(0.7),
+          ),
+        ),
+        const SizedBox(height: AppSpacing.lg),
+        // Individual ExpansionTiles for each Feed Decorator
+        for (final decoratorType in FeedDecoratorType.values)
+          Padding(
+            padding: const EdgeInsets.only(bottom: AppSpacing.md),
+            child: ExpansionTile(
+              title: Text(decoratorType.l10n(context)), // Use localized decorator name
+              childrenPadding: const EdgeInsets.symmetric(
+                horizontal: AppSpacing.xxl,
+              ),
+              children: [
+                FeedDecoratorForm(
+                  decoratorType: decoratorType,
+                  remoteConfig: remoteConfig.copyWith(
+                    feedDecoratorConfig:
+                        Map.from(remoteConfig.feedDecoratorConfig)..putIfAbsent(
+                          decoratorType,
+                          () => FeedDecoratorConfig(
+                            category:
+                                decoratorType == FeedDecoratorType.suggestedTopics ||
+                                    decoratorType == FeedDecoratorType.suggestedSources
+                                ? FeedDecoratorCategory.contentCollection
+                                : FeedDecoratorCategory.callToAction,
+                            enabled: false,
+                            visibleTo: const {},
+                            itemsToDisplay:
+                                decoratorType == FeedDecoratorType.suggestedTopics ||
+                                    decoratorType == FeedDecoratorType.suggestedSources
+                                ? 0
+                                : null,
+                          ),
+                        ),
+                  ),
+                  onConfigChanged: onConfigChanged,
+                ),
+              ],
+            ),
+          ),
+      ],
+    );
+  }
+}