Browser REPL cannot safely accept new connections

Browser REPL current depends on a loop that gets kicked off by `:ready`. From this point forward Browser REPL loops on `:result` from client to get a connection to send evaluations. But this means other REPLs cannot be a part of this loop without interfering with the behavior.

We need the client to make `:accept` requests in order to listen for new connections. This can probably be retried on failure to allow for reconnect.