Make a per-user block one-directional and non-destructive: the blocker stops
receiving everything from the blocked user (chat, nudge, friend requests,
invitations) and the matchmaker never pairs them, while the blocked user
notices nothing — their sends still persist by the normal rules but are never
delivered or surfaced (born-read). A block no longer deletes the friendship
(an unblock cleanly restores it) and instant-reads any unread the blocked user
had left for the blocker.
- backend: a directional blockExists guard across chat/nudge/friends/invitations
(store-but-hide for the blocked->blocker direction, refuse blocker->blocked);
the matchmaker excludes a block-related pair (both directions) from auto-match;
user_blocked/user_unblocked notifications to the blocker only (in-app only).
- ui: the opponent score card gains a block ✖️ control mirroring add-friend
(red "Block?" confirm, mutual-hide while confirming, struck name, hidden chat
composer when blocked); optimistic apply + event confirm + rollback for both.
- admin: the user card gains cross-linked blocks / blocked-by / friends lists.
- docs: FUNCTIONAL(+ru), ARCHITECTURE §10 + decision record, UI_DESIGN, PRERELEASE.