int_ofsted_latest now picks each school's latest visit (report card, graded or ungraded inspection) and the overall grade still in force, dated by the inspection that awarded or confirmed it. A 'School remains Good' from an older ungraded visit is no longer carried past a newer inspection that gave no grade (audit C1). Duplicate monthly rows resolve to the newest visit, so a newer report card always wins. dim_school's columns are unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
