feat(content_management): add archived headlines bloc

- Create ArchivedHeadlinesBloc class with initial state
- Define ArchivedHeadlinesEvent and ArchivedHeadlinesState classes
- Set up basic structure for handling archived headlines events

Author: fulleni

lib/content_management/bloc/archived_headlines/archived_headlines_bloc.dart

@@ -0,0 +1,13 @@
+import 'package:bloc/bloc.dart';
+import 'package:equatable/equatable.dart';
+
+part 'archived_headlines_event.dart';
+part 'archived_headlines_state.dart';
+
+class ArchivedHeadlinesBloc extends Bloc<ArchivedHeadlinesEvent, ArchivedHeadlinesState> {
+  ArchivedHeadlinesBloc() : super(ArchivedHeadlinesInitial()) {
+    on<ArchivedHeadlinesEvent>((event, emit) {
+      // TODO: implement event handler
+    });
+  }
+}

lib/content_management/bloc/archived_headlines/archived_headlines_event.dart

@@ -0,0 +1,8 @@
+part of 'archived_headlines_bloc.dart';
+
+sealed class ArchivedHeadlinesEvent extends Equatable {
+  const ArchivedHeadlinesEvent();
+
+  @override
+  List<Object> get props => [];
+}

lib/content_management/bloc/archived_headlines/archived_headlines_state.dart

@@ -0,0 +1,10 @@
+part of 'archived_headlines_bloc.dart';
+
+sealed class ArchivedHeadlinesState extends Equatable {
+  const ArchivedHeadlinesState();
+  
+  @override
+  List<Object> get props => [];
+}
+
+final class ArchivedHeadlinesInitial extends ArchivedHeadlinesState {}