cachedParticipants returned a participant page with Hash=0 whenever the
channel_base / channel_participants rows in read_model_versions were never
seeded for a channel (e.g. groups created via messages.createChat). With
Hash=0 the RPC layer can never answer channels.channelParticipantsNotModified,
so a client that polls the member list re-fetches it in a tight loop forever.
Fall back to a deterministic content hash derived from the page itself
(channel id, page key, count, and each member's id/role/status/rank) so an
unchanged member list yields an identical non-zero Hash and the client
converges. The read-model-backed path is unchanged.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
