Slack's adapter registers a single parent slash command /hermes and
dispatches subcommands via slack_subcommand_map(). Bare /sethome is
not a registered command on Slack and fails with 'app did not
respond', logging 'Unhandled request' in slack_bolt.AsyncApp.
Show /hermes sethome in the first-run onboarding hint when the
source platform is Slack; keep /sethome for Telegram, Discord,
Matrix, Mattermost, and other platforms that register it directly.
Fixes#14632
d993a3f450