feat: 消息添加未阅读数量

lib/models/msg/msgfeed_unread.dart

@@ -0,0 +1,26 @@
+class MsgFeedUnread {
+  MsgFeedUnread({
+    this.at = 0,
+    this.chat = 0,
+    this.like = 0,
+    this.reply = 0,
+    this.sys_msg = 0,
+    this.up = 0,
+  });
+
+  int at = 0;
+  int chat = 0;
+  int like = 0;
+  int reply = 0;
+  int sys_msg = 0;
+  int up = 0;
+
+  MsgFeedUnread.fromJson(Map<String, dynamic> json) {
+    at = json['at'] ?? 0;
+    chat = json['chat'] ?? 0;
+    like = json['like'] ?? 0;
+    reply = json['reply'] ?? 0;
+    sys_msg = json['sys_msg'] ?? 0;
+    up = json['up'] ?? 0;
+  }
+}