chore(auth): ScadaBridge unify dev LDAP base DN to dc=zb,dc=local (Task 1.6)

Replace dc=scadabridge,dc=local with dc=zb,dc=local in all dev/test LDAP
references — app config, docker test-cluster node configs (docker/ and
docker-env2/), GLAuth fixture, dev tooling, Host.Tests fixtures,
IntegrationTests factory, and operational test_infra docs. OU structure
(ou=SCADA-Admins,ou=users,etc.) preserved throughout. Email domains
(@scadabridge.local), hostnames, and container names are untouched.
Historical plan docs (2026-05-24-second-environment.md,
2026-05-31-folder-repo-rename-scadabridge-design.md) excluded as
point-in-time records. No synthetic dc=example,dc=com placeholders touched.

tests/ZB.MOM.WW.ScadaBridge.Host.Tests/ActorPathTests.cs

@@ -57,8 +57,8 @@ public class CentralActorPathTests : IAsyncLifetime
                         ["ScadaBridge:Security:Ldap:Port"] = "3893",
                         ["ScadaBridge:Security:Ldap:Transport"] = "None",
                         ["ScadaBridge:Security:Ldap:AllowInsecure"] = "true",
-                        ["ScadaBridge:Security:Ldap:SearchBase"] = "dc=scadabridge,dc=local",
-                        ["ScadaBridge:Security:Ldap:ServiceAccountDn"] = "cn=admin,dc=scadabridge,dc=local",
+                        ["ScadaBridge:Security:Ldap:SearchBase"] = "dc=zb,dc=local",
+                        ["ScadaBridge:Security:Ldap:ServiceAccountDn"] = "cn=admin,dc=zb,dc=local",
                     });
                 });
                 builder.UseSetting("ScadaBridge:Node:Role", "Central");