feat: add characters

lib/feature/game/presentation/bloc/game_state.dart

@@ -9,7 +9,9 @@ class LobbyPlayer {
   final String avatar; // seed آواتارِ انتخابیِ کاربر
   final bool host;
   final int seat; // جایگاهِ مطلق (۰..۳)
-  const LobbyPlayer(this.name, this.avatar, this.host, this.seat);
+  final String avatarImg; // شخصیتِ آواتارِ انتخابی (<id>.<ext>؛ خالی ⇒ تصادفی)
+  const LobbyPlayer(this.name, this.avatar, this.host, this.seat,
+      {this.avatarImg = ''});
 
   /// seedِ آواتار برای نمایش: آواتارِ انتخابی، وگرنه نام.
   String get avatarSeed => avatar.isNotEmpty ? avatar : name;
@@ -42,6 +44,7 @@ class TableLobby {
                   (e['avatar'] ?? '') as String,
                   (e['host'] ?? false) as bool,
                   (e['seat'] ?? 0) as int,
+                  avatarImg: (e['avatar_img'] ?? '') as String,
                 ))
             .toList(),
         isHost: (j['host'] ?? false) as bool,