The live AlarmStateUpdate already carried ack_time (24) but the Debug View
snapshot DTO did not, so snapshot-seeded alarm rows showed a null ack time
until the next live update. Additive google.protobuf.Timestamp ack_time = 21
(absent => null, including from a pre-#84 site), vendored C# regenerated with
docker/regen-proto.sh sitecommand, mapped both ways in SiteCommandDtoMapper.
The native golden sample now sets AckTime (the computed one leaves it null),
so the round-trip golden pins both the present and the absent decode.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty
d36825633b