fix(pipeline): dim_school's Ofsted grade is the one still in force

dim_school.ofsted_grade (Typesense's rating) coalesced the graded grade with an older ungraded visit's, so Rabbsfarm's 2020 'remains Good' survived its 2025 no-grade inspection. It now reads int_ofsted_latest's current_grade, and ofsted_date is the latest visit. Unit tests pin both (audit C1, M1).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pipeline/transform/models/marts/dim_school.sql

@@ -71,12 +71,12 @@ select
     s.nursery_provision,
     s.admissions_policy_code,
 
-    -- Latest Ofsted (populated after monthly Ofsted pipeline runs)
+    -- Latest Ofsted (populated after monthly Ofsted pipeline runs). The grade
+    -- still in force and the latest visit, from int_ofsted_latest — never a
+    -- grade carried past a newer inspection.
     {% if ofsted_relation is not none %}
-    -- Prefer the graded overall effectiveness; fall back to the grade parsed
-    -- from the latest ungraded (Section 8) outcome when no graded grade exists.
-    coalesce(o.overall_effectiveness, o.ungraded_grade) as ofsted_grade,
-    o.inspection_date as ofsted_date,
+    o.current_grade as ofsted_grade,
+    o.latest_visit_date as ofsted_date,
     o.framework as ofsted_framework
     {% else %}
     null::text as ofsted_grade,

pipeline/transform/models/marts/dim_school.yml

@@ -0,0 +1,35 @@
+version: 2
+
+unit_tests:
+  - name: dim_school_ofsted_grade_is_the_one_still_in_force
+    description: >
+      Rabbsfarm (102408). Its 2025 inspection gave no overall grade, so the 2020
+      "School remains Good" must not reach dim_school (which feeds Typesense's
+      rating), and ofsted_date is the latest visit (audit C1, M1).
+    model: dim_school
+    given:
+      - input: ref('stg_gias_establishments')
+        rows:
+          - {urn: 102408, school_name: 'Rabbsfarm Primary School', status_code: 1, school_type_code: 1, local_authority_code: 312, phase_code: 2}
+      - input: ref('int_ofsted_latest')
+        rows:
+          - {urn: 102408, inspection_date: '2025-06-17', overall_effectiveness: null, ungraded_grade: 2, framework: 'Schools - S5', latest_visit_date: '2025-06-17', current_grade: null}
+    expect:
+      rows:
+        - {urn: 102408, ofsted_grade: null, ofsted_date: '2025-06-17', ofsted_framework: 'Schools - S5'}
+
+  - name: dim_school_ofsted_grade_keeps_its_own_date_out_of_ofsted_date
+    description: >
+      Washwood Heath (139888). Good from a 2020 graded inspection; latest visit
+      an ungraded one in May 2025. ofsted_date is the latest visit.
+    model: dim_school
+    given:
+      - input: ref('stg_gias_establishments')
+        rows:
+          - {urn: 139888, school_name: 'Washwood Heath Academy', status_code: 1, school_type_code: 28, local_authority_code: 330, phase_code: 7}
+      - input: ref('int_ofsted_latest')
+        rows:
+          - {urn: 139888, inspection_date: '2020-03-03', overall_effectiveness: 2, ungraded_grade: null, framework: 'Schools - S5', latest_visit_date: '2025-05-21', current_grade: 2}
+    expect:
+      rows:
+        - {urn: 139888, ofsted_grade: 2, ofsted_date: '2025-05-21'}