Bulk upsert active units.
Body format: { "units": [ ... ] }
Validation:
idPartner API key provided by Northca.
Discord Guild ID (server/guild context for the request).
Discord User ID for the acting user (optional; used for audit fields).
MDT ID.
Bulk upsert. Each unit must include a non-empty id.
Duplicate ids within the same request are rejected.
Upserted units.
The response is of type any.