Delete groups

Delete up to BATCH_MAX_ITEMS groups in a single request.

Hard-deletes the rows (StudentGroup is not a SoftDeletionModel). All FK-back relations cascade — memberships, visibility overrides, and other link tables are removed by the database. Per-row .delete() fires pre_delete and post_delete naturally, preserving the Salesforce sync receiver and the workflow / analytics cleanup hooks.

Each item is processed independently — a failure on one row does not abort the rest. Response is 200 if all items deleted, 207 if any failed, 400 if the request envelope is empty or over the cap.

Within-batch duplicate detection is first-wins on id: subsequent occurrences are pre-marked duplicate_in_batch (pointing at /data/{i}/id) without reaching the service. This matches the POST and PATCH endpoints' first-wins semantics.

See api_v2/docs/batch-responses.md for the envelope shape.

Required OAuth scope: student-groups:write