Codec only — the app does not compose or act on them yet — but it must
already understand an envelope the iPhone app sends, and more
importantly must not be made to do work by one.
🔴 Bounded and deduplicated on receipt. The list comes off the wire, and
a hostile sender could name ten thousand ids in one envelope; the cost
of that lands on every recipient's device rather than theirs. Capped at
256, far above any real roster.
A malformed list does not break the message: it is an ordinary message
with an odd field, not a reason to drop what somebody wrote.
Refs paulhitt/flamenet-messenger-ios#49
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
