usable property
Whether this build could be released now: processed, and not expired.
The question, rather than the vocabulary. A caller asking this never has to know what Apple's states are, which is the point.
It fails closed, and false therefore does not mean "not usable" — it
means "not known to be usable". A state this version does not name
lands here as false, which is the right default for a flag that gates
an action: refusing to release a build whose state is not understood is
the safe direction. serving is nullable rather than false-by-default
precisely because it gates a report, where false is a claim rather than
a refusal. Two booleans, two consequences, two shapes.
Implementation
final bool usable;