List severe-injury reports

Per-event OSHA Severe Injury Reports (29 CFR 1904.39) for an employer.

Each row is an injury the employer self-reported within 24 hours -- in-patient hospitalization, amputation, or loss of an eye. Distinct from /employers/{id}/inspections (inspection-triggered): SIR is injury-triggered, so the same event may or may not have a related inspection (see inspection_activity_nr -- often NULL).

Metered: one lookup per call, same as inspections / SEC enforcement. Newest event first.