feat: 添加首页图片选择功能（拍照/相册）

apps/test/features/home/ui/screens/home_screen_test.dart

@@ -3,6 +3,7 @@ import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:image_picker/image_picker.dart';
 import 'package:lucide_icons/lucide_icons.dart';
 import 'package:social_app/core/api/api_exception.dart';
 import 'package:social_app/features/chat/data/models/ag_ui_event.dart';
@@ -38,7 +39,7 @@ class _WaitingAgUiService extends AgUiService {
   final Completer<void> _pending = Completer<void>();
 
   @override
-  Future<void> sendMessage(String content) async {
+  Future<void> sendMessage(String content, {List<XFile>? images}) async {
     onEvent(RunStartedEvent(threadId: 't1', runId: 'r1'));
     return _pending.future;
   }