Completes the safety loop. useMuteList reads the viewer's kind-10000 mute
list plus optimistic local mutes (lib/localMutes.ts); useMuteUser
republishes the list with the target added, records it locally and
invalidates content queries. useAdminModeration carries a new
mutedPubkeys set, and the shared filterAdminHidden/filterAdminHiddenMixed
drop muted authors — so every list hook filters them with no per-hook
changes (admin tooling with includeHidden still sees them). The flagged
notice gains a Mute action.
