Resolves an avatar for a given host-supplied peerId. Returning null (or
throwing) falls back to the initials placeholder. The call UI never blocks
on the provider — it shows initials immediately and swaps in the avatar
when the promise resolves. Each peerId is resolved at most once per call.
Resolves an avatar for a given host-supplied
peerId. Returningnull(or throwing) falls back to the initials placeholder. The call UI never blocks on the provider — it shows initials immediately and swaps in the avatar when the promise resolves. EachpeerIdis resolved at most once per call.