add client chat page & chat overlay window

lib/models/chat_model.dart

@@ -1,5 +1,44 @@
+import 'package:dash_chat/dash_chat.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_hbb/pages/chat_page.dart';
+
+import 'model.dart';
+import 'native_model.dart';
 
 class ChatModel with ChangeNotifier {
+  final List<ChatMessage> _messages = [];
 
+  final ChatUser me = ChatUser(
+    name:"me",
+  );
+
+  get messages => _messages;
+
+  receive(String text){
+    if (text.isEmpty) return;
+    // first message show overlay icon
+    if (iconOverlayEntry == null){
+      showChatIconOverlay();
+    }
+    _messages.add(ChatMessage(text: text, user: ChatUser(
+      name:FFI.ffiModel.pi.username,
+      uid: FFI.getId(),
+    )));
+    notifyListeners();
+  }
+
+  send(ChatMessage message){
+    _messages.add(message);
+    if(message.text != null && message.text!.isNotEmpty){
+      PlatformFFI.setByName("chat",message.text!);
+    }
+    notifyListeners();
+  }
+
+  release(){
+    hideChatIconOverlay();
+    hideChatWindowOverlay();
+    _messages.clear();
+    notifyListeners();
+  }
 }

lib/models/model.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/services.dart';
 import 'package:flutter_easyloading/flutter_easyloading.dart';
+import 'package:flutter_hbb/models/chat_model.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'dart:math';
 import 'dart:convert';
@@ -128,6 +129,9 @@ class FfiModel with ChangeNotifier {
         Clipboard.setData(ClipboardData(text: evt['content']));
       } else if (name == 'permission') {
         FFI.ffiModel.updatePermission(evt);
+      } else if (name == 'chat'){
+        // FFI.setByName("chat",msg);
+        FFI.chatModel.receive(evt['text']??"");
       }
     }
     if (pos != null) FFI.cursorModel.updateCursorPosition(pos);
@@ -703,6 +707,7 @@ class FFI {
   static final cursorModel = CursorModel();
   static final canvasModel = CanvasModel();
   static final serverModel = ServerModel();
+  static final chatModel = ChatModel();
 
   static String getId() {
     return getByName('remote_id');
@@ -797,6 +802,7 @@ class FFI {
   }
 
   static void close() {
+    chatModel.release();
     if (FFI.imageModel.image != null && !isDesktop) {
       savePreference(
           id,