The expander comment now records that a SQL outage at central boot exits
pre-Serilog with a bare stderr trace (honest, restart-retryable, unenriched)
and why the role-reading predicate deliberately stays in Program.cs rather
than SecretsRegistration (that class refuses config-read roles by design).
EnsureCentralSharedStoreConnectionString gains the file's standard
ThrowIfNull. The site-purity scan's doc no longer overclaims: two
factory-lambda descriptors evade it individually; the pin holds because
three concrete-type registrations from the same call cannot.
Claude-Session: https://claude.ai/code/session_014WNM4vjoVksyyBraTXSZE1
Joseph Doherty
aebdd56b52