Keeps the node-local chat-moderation ETS tables in sync with the database and the other app instances, and sweeps expired mutes.

After init it loads the blocklist and active mutes into ETS; afterwards it applies changes broadcast by other instances on Gamend.Chat.Moderation.Cache.topic/0. Events originating on this node are skipped — the writer already applied them locally.

The initial load runs in handle_continue and retries rather than failing the boot: init/1 must not couple application startup to the database being reachable (e.g. during a rolling restart on an unmigrated table).

The mute sweep is hygiene only. Cache.muted?/3 ignores an expired entry as it reads it, so a mute never outlives its expiry even if this never runs.