Cron deliveries were mirrored into the target gateway session as
assistant-role messages, causing consecutive assistant messages that
violate message alternation (issue #2221).
Instead of fixing the role, remove the mirror injection entirely.
Cron outputs already live in their own cron session and don't belong
in the interactive conversation history.
Delivered messages are now wrapped with a header (task name) and a
footer noting the agent cannot see or respond to the message, so
users have clear context about what they're reading.
Closes#2221
37a9979459