• Fix automatic spindown resetting the idle timer on disks without
  unique hardware identifiers (e.g., behind USB bridges with duplicate
  serials/WWNs) by only treating transitions from standby to active
  as physical spin-ups.
• Fix scrubbed percentage display in the WebUI when there are zero
  unscrubbed blocks.
• Note that the "touch_zero_subseconds" option requires SnapRAID 15.1
  or newer to function correctly, avoiding a failure with "Invalid
  parity split size -1" on a never-synced array.