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.Auth/src/ZB.MOM.WW.Auth.AspNetCore/ServiceCollectionExtensions.cs

@@ -37,7 +37,14 @@ public static class ServiceCollectionExtensions
         ArgumentNullException.ThrowIfNull(config);
         ArgumentException.ThrowIfNullOrWhiteSpace(sectionPath);
 
-        services.Configure<LdapOptions>(config.GetSection(sectionPath));
+        // Bind via the options builder and opt into start-time validation. An IValidateOptions<T>
+        // otherwise only runs when the options are first materialized (IOptions<T>.Value) — which
+        // here is the first login (ILdapAuthService factory below), not boot. ValidateOnStart hooks
+        // the host's start-time options validation so a misconfigured directory (e.g. insecure
+        // transport without AllowInsecure) fails fast at startup rather than on first login.
+        services.AddOptions<LdapOptions>()
+            .Bind(config.GetSection(sectionPath))
+            .ValidateOnStart();
 
         // Fail fast at startup on a misconfigured directory rather than on first login.
         services.AddSingleton<IValidateOptions<LdapOptions>, LdapOptionsValidator>();