How a Discord message could carry references to our DOs, after
@endo/chat: names in the text, references beside it in a mailbox DO,
an Adopt button answered ephemerally, and per-user petstores. Webkeys
in markdown work but disclose the capability to every channel reader
and to Discord itself; ephemeral replies still pass through Discord,
so references should never cross it at all.
Generated-by: Claude Opus 5.5
