feat: 添加首页图片选择功能（拍照/相册）

apps/test/features/chat/chat_bloc_test.dart

@@ -1,5 +1,6 @@
 import 'package:bloc_test/bloc_test.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:image_picker/image_picker.dart';
 import 'package:social_app/features/chat/data/models/ag_ui_event.dart';
 import 'package:social_app/features/chat/data/models/chat_list_item.dart';
 import 'package:social_app/features/chat/data/services/ag_ui_service.dart';
@@ -9,14 +10,14 @@ class MockAgUiService extends AgUiService {
   MockAgUiService() : super(onEvent: (_) {});
 
   @override
-  Future<void> sendMessage(String content) async {}
+  Future<void> sendMessage(String content, {List<XFile>? images}) async {}
 }
 
 class _ThrowingAgUiService extends AgUiService {
   _ThrowingAgUiService() : super(onEvent: (_) {});
 
   @override
-  Future<void> sendMessage(String content) async {
+  Future<void> sendMessage(String content, {List<XFile>? images}) async {
     throw StateError('network down');
   }
 }