A sweep read what it keeps before what was ever recorded, so a take-in's
build recorded between the two reads, by a concurrent take-in off the
plans' hold, was eligible and let go of seconds after the take-in read
it; a new module's build is unkept until it is registered. Now the sweep
reads the records first and keeps what a build recorded within the hour
or an open plan names, and names every reference it lets go of; a take-in
holds every artifact in the store before recording, failing on one the
store lacks; and RecordBuild clears artifact_collected as RecordMirrored
does.
jschoubben