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.Configuration/tests/ZB.MOM.WW.Configuration.Tests/AddValidatedOptionsTests.cs

@@ -44,4 +44,24 @@ public sealed class AddValidatedOptionsTests
         Assert.Equal("central", opts.Name);
         await host.StopAsync();
     }
+
+    [Fact]
+    public void Calling_twice_registers_validator_once()
+    {
+        var config = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?> { ["Node:Port"] = "0", ["Node:Name"] = "" })
+            .Build();
+        var services = new ServiceCollection();
+        services.AddValidatedOptions<NodeOptions, NodeValidator>(config, "Node");
+        services.AddValidatedOptions<NodeOptions, NodeValidator>(config, "Node");
+
+        using var provider = services.BuildServiceProvider();
+        var validators = provider.GetServices<IValidateOptions<NodeOptions>>().ToArray();
+        Assert.Single(validators);
+
+        // Resolving the options surfaces each accumulated failure exactly once, not doubled.
+        var ex = Assert.Throws<OptionsValidationException>(
+            () => provider.GetRequiredService<IOptions<NodeOptions>>().Value);
+        Assert.Equal(2, ex.Failures.Count());
+    }
 }