Potential experiments

fix(gateway): clamp a heartbeat ack to the session sequence (#2283)

fix(worker): resubscribe when the job stream ends unexpectedly (#2282)

fix(worker): renew the deletion queue lock during a rebuild

fix(gateway): group debounced reactions by their own message (#2281)

chore(expressions): remove the pack residue cleanup tool

fix(gateway): clear the presence pid cache on a presence down (#2279)

fix(worker): stop replaying requeued asset deletions in a run (#2280)

fix(worker): count each channel once in a bulk reindex

fix(gateway): drop the channel engine on an empty range list (#2278)

fix(worker): keep attachment decay state on a stale expiry row

fix(gateway): release the user session count on a handoff fence

fix(gateway): stop a non-map opcode payload crashing the socket (#2277)

fix(gateway): clamp a heartbeat ack to the session sequence

fix(gateway): keep the replay buffer across a session transfer (#2276)

fix(worker): catch up cron jobs missed by a delayed tick (#2275)

fix(worker): drain in-flight jobs before the runner stops (#2274)

fix(gateway): flush buffered presences in arrival order (#2273)

fix(cache): refcount produce tracking so deletes are not lost (#2272)

fix(ci): install rustup before use on cold runners

fix(desktop): accept array-form AppRun sandbox fallback (#2271)