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.Theme/tests/ZB.MOM.WW.Theme.Tests/NavRailTests.cs

@@ -13,6 +13,28 @@ public class NavRailTests : TestContext
         Assert.Contains("Clusters", a.TextContent);
     }
 
+    // Theme-004: when Icon is supplied it is wrapped in a .rail-ico span (now styled).
+    [Fact]
+    public void NavRailItem_wraps_icon_in_rail_ico_span_when_supplied()
+    {
+        var cut = RenderComponent<NavRailItem>(p => p
+            .Add(x => x.Href, "/clusters")
+            .Add(x => x.Text, "Clusters")
+            .Add(x => x.Icon, (RenderFragment)(b => b.AddMarkupContent(0, "<svg class='ico'/>"))));
+        var ico = cut.Find("a.rail-link .rail-ico");
+        Assert.NotNull(ico);
+        Assert.NotNull(cut.Find("a.rail-link .rail-ico .ico"));
+    }
+
+    [Fact]
+    public void NavRailItem_omits_rail_ico_span_when_no_icon()
+    {
+        var cut = RenderComponent<NavRailItem>(p => p
+            .Add(x => x.Href, "/clusters")
+            .Add(x => x.Text, "Clusters"));
+        Assert.Empty(cut.FindAll(".rail-ico"));
+    }
+
     [Fact]
     public void NavRailSection_renders_title_and_children_open_by_default()
     {