DEFAULT_DWELL_MINUTES
Minutes to dwell on each preset by default.
Deliberately short. The dwell is per preset, so this multiplies: at the previous default of 15 a three-preset sweep ran for 45 minutes, which outlived the wake lock that keeps the CPU up for it. Longer dwells hear more, so every previous option is still offered in the picker — this only changes what an untouched first scan costs.