better report user bot upgrade error

app/controllers/PlayApi.scala

@@ -38,7 +38,10 @@ final class PlayApi(
             case _ =>
               env.user.repo.setBot(me) >>
                 env.pref.api.setBot(me) >>-
-                env.user.lightUserApi.invalidate(me.id) pipe toResult
+                env.user.lightUserApi.invalidate(me.id) pipe
+                toResult recover {
+                case lila.base.LilaInvalid(msg) => BadRequest(jsonError(msg))
+              }
           }
         case _ => impl.command(me, cmd)(WithPovAsBot)
       }

modules/common/src/main/base/LilaException.scala

@@ -9,6 +9,8 @@ trait LilaException extends Exception {
   override def toString   = message
 }
 
+case class LilaInvalid(message: String) extends LilaException
+
 object LilaException extends scalaz.syntax.ToShowOps {
 
   def apply(msg: String) =

modules/user/src/main/UserRepo.scala

@@ -484,7 +484,8 @@ final class UserRepo(val coll: Coll)(implicit ec: scala.concurrent.ExecutionCont
   def isManaged(id: ID): Fu[Boolean] = email(id).dmap(_.exists(_.isNoReply))
 
   def setBot(user: User): Funit =
-    if (user.count.game > 0) fufail("You already have games played. Make a new account.")
+    if (user.count.game > 0)
+      fufail(lila.base.LilaInvalid("You already have games played. Make a new account."))
     else coll.updateField($id(user.id), F.title, Title.BOT).void
 
   private def botSelect(v: Boolean) =