Feature request: psql --idle

Since changing ph_hda.conf file to give users access involves the restart
of server, many companies I work(ed) use a bastion host, where users ssh
to, and are allowed "somehow" use postgresql.

Still, those users need some login shell.

It would be great to give them psql as a login shell (in /etc/passwd).
But doing so, will result in psql exiting with error with the usual
$ psql
psql: error: connection to server on socket "/tmp/.s.PGSQL.5432" failed: No
such file or directory
Is the server running locally and accepting connections on that socket?

What would help, is a --idle option, where psql does not exit, stays idle
and waits for user to give a \conn command.
Something similar to
sqlplus /nolog

Is anything like that feasible or is there another solution/workaround?

Tnx!