feat: Create manage followed items page

- Added navigation to lists
- Supports category, source, country

Author: fulleni

lib/account/view/manage_followed_items_page.dart

@@ -0,0 +1,63 @@
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import 'package:ht_main/l10n/l10n.dart';
+import 'package:ht_main/router/routes.dart'; // Assuming new routes will be added here
+import 'package:ht_main/shared/constants/app_spacing.dart';
+
+/// {@template manage_followed_items_page}
+/// Page for navigating to lists of followed content types like
+/// categories, sources, and countries.
+/// {@endtemplate}
+class ManageFollowedItemsPage extends StatelessWidget {
+  /// {@macro manage_followed_items_page}
+  const ManageFollowedItemsPage({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final l10n = context.l10n;
+
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(l10n.accountContentPreferencesTile), // "Content Preferences"
+      ),
+      body: ListView(
+        padding: const EdgeInsets.symmetric(vertical: AppSpacing.md),
+        children: [
+          ListTile(
+            leading: const Icon(Icons.category_outlined),
+            title: Text(l10n.headlinesFeedFilterCategoryLabel), // "Categories"
+            trailing: const Icon(Icons.chevron_right),
+            onTap: () {
+              // TODO(cline): Replace with actual route name once defined
+              // context.goNamed(Routes.followedCategoriesListName);
+              print('Navigate to Followed Categories List Page');
+            },
+          ),
+          const Divider(indent: AppSpacing.lg, endIndent: AppSpacing.lg),
+          ListTile(
+            leading: const Icon(Icons.source_outlined),
+            title: Text(l10n.headlinesFeedFilterSourceLabel), // "Sources"
+            trailing: const Icon(Icons.chevron_right),
+            onTap: () {
+              // TODO(cline): Replace with actual route name once defined
+              // context.goNamed(Routes.followedSourcesListName);
+              print('Navigate to Followed Sources List Page');
+            },
+          ),
+          const Divider(indent: AppSpacing.lg, endIndent: AppSpacing.lg),
+          ListTile(
+            leading: const Icon(Icons.public_outlined),
+            title: Text(l10n.headlinesFeedFilterEventCountryLabel), // "Countries"
+            trailing: const Icon(Icons.chevron_right),
+            onTap: () {
+              // TODO(cline): Replace with actual route name once defined
+              // context.goNamed(Routes.followedCountriesListName);
+              print('Navigate to Followed Countries List Page');
+            },
+          ),
+          const Divider(indent: AppSpacing.lg, endIndent: AppSpacing.lg),
+        ],
+      ),
+    );
+  }
+}