Command a Metasys point (write a setpoint) at a specific BACnet write priority

Documented steps

1. Authenticate and resolve the point to an objectId.
2. GET {base}/objects/{objectId}/commands to discover what the object actually supports. The response is {self, items[], effectivePermissions}.
3. For each item read 'id' (e.g. 'commandIdEnumSet.adjustCommand'), 'invokeUrl', 'title' and 'commandBodySchema'. The commandBodySchema tells you the exact shape and arity of 'parameters' for that command on that object type.
4. Check effectivePermissions.canInvoke - it lists the command ids the current user is allowed to invoke. Do not attempt a command absent from that list.
5. PUT the command: PUT {base}/objects/{objectId}/commands/adjustCommand with body {"parameters":[72.5],"priority":"writePriorityEnumSet.priority12","annotation":"raise setpoint"}. The short command id ('adjustCommand') is accepted in the path in place of the fully qualified enum name.
6. Expect HTTP 202 Accepted with no response body. Treat 202 as 'accepted for execution', not 'value is now committed'.
7. Confirm the write by re-reading the attribute (GET /objects/{objectId}/attributes/presentValue) and inspecting 'condition.presentValue.priority' to see the priority that is actually in control.
8. Choose the priority from writePriorityEnumSet: priorityNone, priorityManualEmergency, priorityFireApplications, priority3, priority4, priorityCriticalEquipment, priorityMinimumOnOff, priorityHeavyEquipDelay, priorityOperatorOverride, priority9, priority10, priorityDemandLimiting, priority12, priorityLoadRolling, priority14, prioritySchedulingOst, priorityDefault.
9. Optionally send header METASYS-FEATURE: standard-error to receive the modern standardErrorMessage error payload instead of the legacy errorMessage shape on 400.
10. Reference: https://jci-metasys.github.io/api-landing/api/v6-16 (Metasys REST API, 'Version 6 for 16.0', OpenAPI 3.0.3). Doc set index: https://jci-metasys.github.io/api-landing/ | changelog: https://jci-metasys.github.io/api-landing/guides/api-changelog/ | version support: https://jci-metasys.github.io/api-landing/guides/version-support-matrix/ | polling and streaming limits: https://jci-metasys.github.io/api-landing/guides/attribute-access-guidelines/