Coordinated cross-repo epic to restore the three v1 alarm capabilities
that PR 7.2 regressed: rich MxAccess alarm-event metadata, native
Acknowledge semantics, and the IAlarmHistorianWriter write-back path.
Architectural split: gateway owns MxAccess transport (new
OnAlarmTransition event family + AcknowledgeAlarm / QueryActiveAlarms /
WriteHistorianEvent RPCs); lmxopcua keeps the OPC UA Part 9 state
machine, ACL/role enforcement, and multi-source aggregation. The
existing value-driven sub-attribute path stays as fallback.
10 PRs total — 5 in mxaccessgw, 5 in lmxopcua — sequenced so each
side's work is independently reviewable. End-of-epic gate is a parity
matrix run with five new alarm scenarios.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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