MapStatusCode returned Uncertain for any non-zero non-Bad code, so GoodLocalOverride,
GoodClamped and info-bit Good variants degraded to Uncertain. Now top two bits decide:
00 Good, 01 Uncertain, 10/11 Bad (BadResourceUnavailable stays Bad, #112 untouched).
The SDK IsGood/IsUncertain(uint) helpers were tried first and failed the subcode tests,
so an explicit mask is used. MxGateway mapper uses the OPC-DA quality byte (>=192 Good)
and is not affected.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty