type ReplayKey = (String, String, String);Expand description
Tracks (route_id, event_name, scope) tuples whose persisted
history has already been replayed to a given route. Skipping
replay on resubscribe prevents the frontend’s eventsub
flushes (sent on every listener add/remove, once per conn_id)
from re-emitting completed bash logs on every pane mount or
tab switch. Codex P2 on PR #817; route keying updated PR #1418.