pino-pretty's translateTime: "HH:MM:ss" formats all timestamps in UTC,
ignoring the process TZ environment variable. Changing the prefix to
"SYS:HH:MM:ss" instructs pino-pretty to format timestamps in the local
system timezone, so operators running in non-UTC zones see correct
wall-clock times in both the console and the server.log file.
Fixes: #2879
