Load the theta42 (dateOfBirth) schema in the all-in-one image

The app (nodejs/models/user_ldap.js) adds objectClass theta42Person whenever a
user has a dateOfBirth, and lists it among every new user's objectClasses. But
the all-in-one image's static slapd.conf only included core/cosine/inetorgperson/
nis — never the project's own theta42 schema — so slapd rejects
objectClass: theta42Person with LDAP 0x15 (objectClass: value #0 invalid per
syntax). Symptom: PUT /api/user/<uid> (and user creation) failing.

ops/ldap-setup.sh loads this schema for bare-metal (as a cn=config LDIF); the
Docker image uses slapd.conf, so ship it as a .schema file and include it.

- ops/schema/theta42.schema: dateOfBirth attribute + theta42Person auxiliary
  objectClass (same OIDs/definition as ldap-setup.sh section 5).
- Dockerfile.openldap: COPY it to /etc/openldap/schema/theta42.schema.
- docker-entrypoint.sh: include it in the generated slapd.conf (after nis).

Co-Authored-By: Claude <noreply@anthropic.com>

docker-entrypoint.sh

@@ -78,6 +78,7 @@ include         /etc/openldap/schema/core.schema
 include         /etc/openldap/schema/cosine.schema
 include         /etc/openldap/schema/inetorgperson.schema
 include         /etc/openldap/schema/nis.schema
+include         /etc/openldap/schema/theta42.schema
 
 # Module loading (pw-sha2 provides {SSHA512} used by the app for user passwords;
 # ppolicy/memberof/refint are the overlays the app depends on). On OpenLDAP 2.5+