Module cleanup 

Periodic sweep that DELs sessions whose bound client has been gone for more than STALE_AFTER.

Sessions intentionally outlive their clients (Session no longer has a belongs_to(Client) cascade) so the roster can show a brief “disconnected” indicator across reconnect blips. Without this sweeper that grace period would last forever — abandoned sessions would accumulate in the registry and the on-disk log.

Tracking is in-memory: a disconnected_since map records the first tick on which each session was observed disconnected. Daemon restart resets it, which is fine — every session loaded from disk gets a fresh 10-second grace window before it can be swept, giving its shim time to reconnect.

Constants

STALE_AFTER

How long a session must be without a live client before it is DEL’d.

TICK_INTERVAL

How often the sweeper wakes up to check for stale sessions. Anything roughly under STALE_AFTER is fine; the trade-off is reaction latency (lower) vs. wake-ups per minute (higher).

Functions

run_sweeper

Run the sweeper forever. Spawn this on a tokio task and forget it.