remove wifi config, scan for networks using luci, connect. then add secondary interface (AP) and apply changes. if at this point it doesn't work then there is more fun to be had with interfaces/firewall assignment which seems to behave odd for at least a year
A non-WDS client cannot be placed in a bridge such as the default br-lan. It needs to be the only thing attached to its own network that is not a bridge.
A WDS client can be placed in a bridge, but the AP must support WDS or it will not connect.
AP interfaces on the same radio as a client will not start up until the client has connected to its AP.