When checks stop

If a market has funded orders but no check is scheduled, the Trade page and the order page show Checks stopped with a Restart checks button, and sweepStatus(market) returns Stalled. Anyone can call restartSweep(market); they pay only the scheduling fee. It can happen when:

• The vault can't pay for a scheduled call. Hedera reserves gas limit × gas price from the vault when the sweep runs, and a failed payment is dropped without an event. The vault always holds every order's budget, so keep a few HBAR of surplus in it (don't withdraw it all).
• HSS rejects a schedule (SweepScheduleFailed), for example when a second is already full.

Topping up an order also restarts a stopped market.