Thanks! The following appears to work:

    my $s = "Hi, Mom!\n";
#    print "Content-disposition: inline; filename=docket.csv\n";
    print "Content-disposition: attachment; filename=docket.csv\n";
    print "Content-length: " . length($s) . "\n";
    print "Content-type: application/octet-stream\n\n";
    print $s;
[download]

Specifying inline or attachment appears to work in the same manner.

Is there a way to display the standard file-open dialog such that the user can rename the file as desired?

Thanks, again!