Interpret statusFlags, outOfService, reliability and eventState to tell a trustworthy live BACnet value from a stale, overridden or faulted one

Documented steps

1. Read the trust signals in the same request as the value: await app.read_property_multiple(address, [objid, ['present-value','status-flags','event-state','reliability','out-of-service']]).
2. Decode status-flags as a four-bit BitString. The verified bit order in bacpypes3.basetypes.StatusFlags is inAlarm=0, fault=1, overridden=2, outOfService=3.
3. Treat fault=True, or a reliability other than no-fault-detected, as do-not-trust. The standard reliability enumeration includes no-sensor, over-range, under-range, open-loop, shorted-loop, communication-failure, unreliable-other, process-error and configuration-error.
4. Treat overridden=True or out-of-service=True as this is not the physical process value. The point is forced by an operator or detached from real I/O, so present-value reflects a human decision, not field conditions.
5. Treat inAlarm=True together with event-state other than normal as currently in an offnormal condition. Standard event-state values include normal, fault, offnormal, highLimit, lowLimit and lifeSafetyAlarm.
6. Only pass a reading downstream as clean when inAlarm, fault, overridden and out-of-service are all False and reliability, where present, is no-fault-detected. Otherwise annotate the record with the reason.
7. Where reliability is not implemented (it is optional on many object types), fall back to the fault bit of status-flags as the primary trust signal.
8. Access requirement: none at the protocol level; these are ordinary unauthenticated property reads.
9. Official documentation verified 2026-07-30: https://raw.githubusercontent.com/JoelBender/BACpypes3/main/bacpypes3/basetypes.py | https://raw.githubusercontent.com/JoelBender/BACpypes3/main/bacpypes3/object.py