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.

infra/tools/ldap_tool.py

@@ -9,10 +9,10 @@ from ldap3 import Server, Connection, NONE, SUBTREE, SIMPLE
 
 DEFAULT_HOST = "localhost"
 DEFAULT_PORT = 3893
-DEFAULT_BASE_DN = "dc=scadabridge,dc=local"
+DEFAULT_BASE_DN = "dc=zb,dc=local"
 # GLAuth places users under ou=<PrimaryGroupName>,ou=users,dc=...
 # The admin user (primarygroup SCADA-Admins) needs search capabilities in config.
-DEFAULT_BIND_DN = "cn=admin,ou=SCADA-Admins,ou=users,dc=scadabridge,dc=local"
+DEFAULT_BIND_DN = "cn=admin,ou=SCADA-Admins,ou=users,dc=zb,dc=local"
 DEFAULT_BIND_PASSWORD = "password"
 
 
@@ -48,7 +48,7 @@ def cmd_check(args):
 def cmd_bind(args):
     """Test user authentication via bind.
 
-    GLAuth DN format: cn=<user>,ou=<PrimaryGroup>,ou=users,dc=scadabridge,dc=local
+    GLAuth DN format: cn=<user>,ou=<PrimaryGroup>,ou=users,dc=zb,dc=local
     Since we don't know the user's primary group upfront, we search for the user first
     to discover the full DN, then rebind with that DN.
     """