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

Replace all dev-directory dc=lmxopcua,dc=local references with dc=zb,dc=local
across LdapOptions default, integration harness overrides, docker-compose LDAP_ROOT,
AclEdit placeholder DN, and dev/smoke-test docs. CN/OU prefixes preserved.

docs/v2/implementation/phase-7-e2e-smoke.md

@@ -104,8 +104,8 @@ Anonymous OPC UA sessions are denied writes against `Operate`-classified tags by
       "Enabled": true,
       "Server":  "localhost",
       "Port":    3893,
-      "SearchBase": "dc=lmxopcua,dc=local",
-      "ServiceAccountDn": "cn=serviceaccount,dc=lmxopcua,dc=local",
+      "SearchBase": "dc=zb,dc=local",
+      "ServiceAccountDn": "cn=serviceaccount,dc=zb,dc=local",
       "ServiceAccountPassword": "serviceaccount123",
       "GroupToRole": {
         "ReadOnly":       "ReadOnly",