Create labeled associations between HubSpot CRM objects using Associations API v4

Steps

1. Define a custom association label via POST to /crm/v4/associations/{fromObjectType}/{toObjectType}/labels with a label string and an optional inverseLabel for the reverse direction
2. Note the returned typeId values for both directions of the label — you will need these when creating association records
3. Create an association with a specific label by POST to /crm/v4/objects/{fromObjectType}/{fromObjectId}/associations/{toObjectType}/{toObjectId} with a JSON body containing an associationTypes array where each entry specifies associationCategory (HUBSPOT_DEFINED or USER_DEFINED) and associationTypeId
4. Retrieve all associations with their labels for a given object via GET /crm/v4/objects/{objectType}/{objectId}/associations/{toObjectType}; the response includes label metadata alongside each association
5. To batch-create labeled associations, POST to /crm/v4/associations/{fromObjectType}/{toObjectType}/batch/create with an inputs array where each entry specifies from.id, to.id, and the associationTypes array
6. Remove a specific label from an association without deleting the association entirely by using the label-specific DELETE endpoint rather than the full association DELETE