Batch-create HubSpot v4 associations between many record pairs

Steps

1. Use POST /crm/v4/associations/{fromObjectType}/{toObjectType}/batch/create to associate multiple record pairs in a single API call
2. Build the request body as an inputs array where each element contains fromObjectId, toObjectId, and an array of associationTypes each with typeId and, optionally, category
3. Limit each batch to the documented maximum inputs per request; consult current docs for the current batch size limit
4. Process the response's errors array; a partial-failure response still returns a 207 status with successfully created associations and a list of failed ones
5. Retry failed inputs individually or in a smaller batch after resolving the error (e.g., object not found, duplicate association)
6. Use batch/read and batch/archive endpoints analogously for bulk reads and deletes