Code-verified current-state docs for OtOpcUa (three-tier full), ScadaBridge
(two-tier, no /healthz), and MxAccessGateway (bare liveness only / no probes).
GAPS backlog with P1 for MxGateway and convergence items for Akka status policy,
DB probe technique, and response writer. README with per-project status table.
Joseph Doherty