Fix all baseline code-review findings across the six shared libraries

Resolves the 35 findings from the 2026-06-01 baseline (commit 26ba1c7),
test-first for every behavioral change. +51 tests (331 -> 382 passing, 0 failed).

- Telemetry-001 (HIGH): RedactionEnricher now honours property removal, so a
  redactor that drops a key actually scrubs the secret from the event.
- Auth: LDAP validator ValidateOnStart; API-key verify no longer fails on a
  best-effort MarkUsed write or a corrupt scopes column (fail-closed); LDAP cert
  validation hook; KeyPrefix persistence aligned; README algorithm corrected.
- Health: Akka checks return Degraded (not throw) when the cluster isn't up yet;
  GrpcDependencyHealthCheck catch-all; null 'description' rendered; composite
  endpoint builder; XML docs shipped.
- Audit: CompositeAuditWriter no longer re-throws OperationCanceledException;
  TruncatingAuditRedactor over-redact scrubs Target + safe negative max; options
  record; XML docs shipped.
- Configuration: TryAddEnumerable idempotent registration; consistent port
  quoting; strict invariant port parsing; XML docs + README packaged.
- Theme: mobile toggle is now CSS-only (no Bootstrap JS); token/CSS hygiene;
  XML docs on the public parameter surface.

Shared-contract/spec docs updated where the code was the source of truth
(observability service.instance.id, MapZbMetrics, redactor reach). All changes
additive/back-compatible at v0.1.0. code-reviews bookkeeping follows separately.

ZB.MOM.WW.Health/src/ZB.MOM.WW.Health.Akka/ActiveNodeHealthCheck.cs

@@ -103,27 +103,41 @@ public sealed class ActiveNodeHealthCheck : IHealthCheck
         if (system is null)
             return Task.FromResult(HealthCheckResult.Degraded("ActorSystem not yet available."));
 
-        var cluster = Cluster.Get(system);
-        var self = cluster.SelfMember;
-        var selfUp = self.Status == MemberStatus.Up;
-
+        MemberStatus selfStatus;
+        bool selfUp;
         bool hasRole;
         bool isLeader;
-        if (_role is null)
+        try
         {
-            hasRole = false;
-            var leader = cluster.State.Leader;
-            isLeader = leader is not null && leader == self.Address;
+            // Reading cluster membership can throw while the ActorSystem exists but the cluster has
+            // not finished initialising (e.g. Akka.Cluster not yet configured →
+            // ConfigurationException). The spec's startup-safety rule maps this to Degraded rather
+            // than letting the exception escape (which the host would record as Unhealthy).
+            var cluster = Cluster.Get(system);
+            var self = cluster.SelfMember;
+            selfStatus = self.Status;
+            selfUp = selfStatus == MemberStatus.Up;
+
+            if (_role is null)
+            {
+                hasRole = false;
+                var leader = cluster.State.Leader;
+                isLeader = leader is not null && leader == self.Address;
+            }
+            else
+            {
+                hasRole = self.HasRole(_role);
+                var roleLeader = cluster.State.RoleLeader(_role);
+                isLeader = roleLeader is not null && roleLeader == self.Address;
+            }
         }
-        else
+        catch (Exception ex) when (ex is not OperationCanceledException)
         {
-            hasRole = self.HasRole(_role);
-            var roleLeader = cluster.State.RoleLeader(_role);
-            isLeader = roleLeader is not null && roleLeader == self.Address;
+            return Task.FromResult(HealthCheckResult.Degraded("Akka cluster state not yet accessible.", ex));
         }
 
         var health = ActiveNodeDecision.Evaluate(selfUp, isLeader, hasRole, _role);
-        var description = DescribeResult(health, self.Status, selfUp, isLeader);
+        var description = DescribeResult(health, selfStatus, selfUp, isLeader);
         var result = health switch
         {
             HealthStatus.Healthy   => HealthCheckResult.Healthy(description),

ZB.MOM.WW.Health/src/ZB.MOM.WW.Health.Akka/AkkaClusterHealthCheck.cs

@@ -8,7 +8,8 @@ namespace ZB.MOM.WW.Health.Akka;
 /// <summary>
 /// Health check that maps the local node's Akka cluster membership status to a
 /// <see cref="HealthStatus"/> through a configurable <see cref="AkkaClusterStatusPolicy"/>.
-/// Register to the <see cref="ZbHealthTags.Ready"/> tag (recommended <c>[ready, active]</c>).
+/// Register to the <see cref="ZbHealthTags.Ready"/> tag only — cluster membership is a readiness
+/// concern; the <see cref="ZbHealthTags.Active"/> tier is reserved for the leader / active-node probe.
 /// </summary>
 /// <remarks>
 /// The <see cref="ActorSystem"/> is resolved lazily from the service provider. If it is not yet
@@ -42,7 +43,21 @@ public sealed class AkkaClusterHealthCheck : IHealthCheck
         if (system is null)
             return Task.FromResult(HealthCheckResult.Degraded("ActorSystem not yet available."));
 
-        var status = Cluster.Get(system).SelfMember.Status;
+        MemberStatus status;
+        try
+        {
+            // Cluster.Get(system).SelfMember can throw while the ActorSystem exists but the cluster
+            // has not finished initialising (e.g. Akka.Cluster not yet configured →
+            // ConfigurationException). The spec's startup-safety rule maps this to Degraded, not an
+            // escaping exception (which the host would record as Unhealthy and pull the node from
+            // rotation).
+            status = Cluster.Get(system).SelfMember.Status;
+        }
+        catch (Exception ex) when (ex is not OperationCanceledException)
+        {
+            return Task.FromResult(HealthCheckResult.Degraded("Akka cluster state not yet accessible.", ex));
+        }
+
         var health = _policy.Evaluate(status);
         var description = $"Akka cluster member status: {status}";
         var result = health switch