Salvage of #37865 by @verybigdog. Adds delivery_mode (notify / notify+wake / wake)
on kanban notify subscriptions, persists chat_type + user_id_alt so a woken turn
reconstructs the creator's real session key, inherits the return path to child
tasks, and keeps wake out of the model-exposed send_message schema.
Original commits were authored under a local placeholder identity
(hermes-agent@users.noreply.local); re-attributed to the contributor's
public email.
6e81ce273c