feat: 添加首页图片选择功能（拍照/相册）

apps/lib/features/chat/presentation/bloc/chat_bloc.dart

@@ -1,6 +1,7 @@
 import 'dart:convert';
 
 import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:image_picker/image_picker.dart';
 import 'package:social_app/core/api/i_api_client.dart';
 import 'package:social_app/core/api/mock_api_client.dart';
 import 'package:social_app/core/di/injection.dart';
@@ -367,7 +368,7 @@ class ChatBloc extends Cubit<ChatState> {
         .reduce((a, b) => a.isBefore(b) ? a : b);
   }
 
-  Future<void> sendMessage(String content) async {
+  Future<void> sendMessage(String content, {List<XFile>? images}) async {
     final userMessage = TextMessageItem(
       id: 'user-${DateTime.now().millisecondsSinceEpoch}',
       content: content,
@@ -385,7 +386,7 @@ class ChatBloc extends Cubit<ChatState> {
       ),
     );
     try {
-      await _service.sendMessage(content);
+      await _service.sendMessage(content, images: images);
     } catch (error) {
       emit(
         state.copyWith(