removeStaleServerStateUpdatesForDevice
fun removeStaleServerStateUpdatesForDevice(deviceId: UInt, deviceDSC: Int, deviceSSC: Int): ServerGeneratedPersistedPayload?
Removes stale server state updates for a device, based on its current DSC and SSC.
Returns the updated persisted payload if changes were made, null if:
no payload file exists,
no updates were removed,
or an error occurred during decode/encode.
If all updates are stale, the file is deleted and null is returned.