wback 7.4.0

[7.4.0] - 2026-08-25

Added

• app:validate now warns when a site's file source exists but is empty. The
  nightly refuses an empty source, so validate said [ ok ] about a site that
  was guaranteed to fail — test.hampelgroup.net was green in validate for as
  long as it existed, and the 03:17 run is what found it. What validate warns
  about mirrors what the stage refuses, which is how the sync check beside it
  already worked; files simply never got the same treatment. It is a warning and
  not a failure, so the exit code is unchanged and a deploy gating on
  app:validate cannot start failing because of it.