channels: give kicked/banned/promoted/transferred users a real qts so their client applies it

updateChannelParticipant carries the account's qts per the MTProto spec, but
the server always sent Qts: 0, so real clients silently discarded it as a
stale duplicate -- the banned/kicked user's channel never vanished locally
and no correct "removed by admin" message showed, even though the update was
delivered successfully at the transport layer.

Add a durable per-device qts queue (channel_participant_event_queue) sharing
its qts number space with the existing secret-chat queue (one qts sequence
per device, per spec), and use it to stamp a correct, monotonically
increasing qts on the update for every device of the affected user -- for
channel bans/kicks, admin promotion/demotion, and ownership transfer. A
device offline when it happened can now recover the event via
updates.getDifference instead of missing it permanently.

deploy/migrations/20260915000001_channel_participant_event_queue.down.sql

@@ -0,0 +1 @@
+DROP TABLE IF EXISTS public.channel_participant_event_queue;