Live HistorianGateway boot caught that the expander scanned a '_secretsComment' appsettings
value documenting the ${secret:...} syntax, tried to resolve the literal example token, and
crashed boot. The family uses _*Comment keys pervasively, so skip any config key whose leaf
segment starts with '_' (the _comment convention). Functional keys never lead with '_'.
Reference-consumer (HistorianGateway) caught that SecretsAuthorization.AdminRole was
'administrator' (lowercase) while the family canonical role is CanonicalRole.Administrator.
ASP.NET role claims compare case-sensitively (Ordinal), so a real admin got 403 on the
secrets UI. Now nameof(CanonicalRole.Administrator).