Prototype administrative discussion mute controls

Let owners/operators mute or unmute new public/private sends from a human seat while retaining history, incoming messages, gameplay and credentials. Fence metadata and durable audit writes with live authority, membership and versions. Preserve exact admin/message retries and inherit restrictions through seat recovery.

Validation: types/lint, 5431 offline tests, build, 52 HTTP integration tests, 24 administrator HTTP groups, independent SQL/privacy/UI review and desktop/mobile refresh acceptance. All 2230 prior games and 4746 seats preserved. Additive migration 0016. Verified runtime fingerprint 588967fbb9c2e3b6abe2990c4fce96ee69e2256fb7e3ee416314b87593cebba9; documentation-only grammar/button-label review gives b5e57bdd26812debede91c588e38f247f1fa895ad23e7ae30bc8550eedcd90ec. New-revision deployed acceptance remains open; full admin/rules scope is unfinished.

docs/TABLE_DISCUSSION.md

@@ -28,6 +28,16 @@ resumes updates. Channel changes discard obsolete read results. There are no
 public direct-message counts, typing indicators or global sequence numbers.
 Messages are stored durably; pagination does not delete old history.
 
+## Discussion moderation
+
+An administrator can [mute new messages from a seat](ADMIN_DISCUSSION.md). The
+player sees a persistent explanation; reading history, receiving messages and
+playing remain available. The setting follows recovery or handover and is never
+shown as another player's private activity. New sends are checked at database
+commit. An exact previously committed send can still be confirmed while muted;
+no new message is created. Refresh availability after an unmute, or allow the
+normal latest-message poll to update the controls.
+
 ## Saved retries and state isolation
 
 The browser saves an exact message UUID, recipient and body in tab storage before