Slack slash commands (/q, /btw, /stop, /model, etc.) previously showed
no user-visible acknowledgement and posted command replies as public
channel messages. This diverged from Discord, which uses ephemeral
deferred responses for slash commands.
Changes:
- handle_hermes_command now passes response_type='ephemeral' and a
'Running /cmd…' text to ack(), giving the user immediate 'Only visible
to you' feedback when they invoke any native slash command.
- _handle_slash_command stashes the Slack response_url from the command
payload in a per-channel context dict before dispatching to
handle_message.
- send() checks for a pending slash context and, when found, POSTs to
the response_url with replace_original=true to swap the initial ack
with the real command reply (e.g. 'Queued for the next turn.'),
keeping it ephemeral.
- Stale slash contexts are garbage-collected on lookup (120s TTL).
- The response_url POST is non-fatal: if it fails, the user already saw
the initial ack, and send() returns success=True.
Fixes#18182
7cda0e5224