feat(pipeline): add fact_ofsted_latest, one current Ofsted status per school

The backend will read this instead of picking the latest row of fact_ofsted_inspection itself (twice, with arbitrary ties). Schema tests and assert_ofsted_current_grade_consistent pin its invariants. Built by the monthly Ofsted DAG (int_ofsted_latest+), not the daily one.

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

pipeline/transform/models/marts/_marts_schema.yml

@@ -125,6 +125,30 @@ models:
       - name: inspection_date
         tests: [not_null]
 
+  - name: fact_ofsted_latest
+    description: >
+      Current Ofsted status, one row per URN: the latest visit and the overall
+      grade still in force. See int_ofsted_latest for the rule.
+    columns:
+      - name: urn
+        tests: [not_null, unique]
+      - name: latest_visit_date
+        tests: [not_null]
+      - name: latest_visit_kind
+        tests:
+          - not_null
+          - accepted_values:
+              values: ['report_card', 'graded', 'ungraded']
+      - name: current_grade
+        tests:
+          - accepted_values:
+              values: [1, 2, 3, 4]
+              quote: false
+      - name: current_grade_basis
+        tests:
+          - accepted_values:
+              values: ['graded', 'confirmed']
+
   - name: fact_pupil_characteristics
     description: Pupil demographics — one row per URN per year
     columns:

pipeline/transform/models/marts/fact_ofsted_latest.sql

@@ -0,0 +1,37 @@
+-- Mart: current Ofsted status — one row per URN
+-- The backend reads this instead of choosing the latest row of
+-- fact_ofsted_inspection itself. The rule lives in int_ofsted_latest.
+
+select
+    urn,
+    latest_visit_date,
+    latest_visit_kind,
+    latest_visit_outcome,
+    current_grade,
+    current_grade_date,
+    current_grade_basis,
+    graded_inspection_date,
+    ungraded_inspection_date,
+    rc_inspection_date,
+    inspection_type,
+    framework,
+    overall_effectiveness,
+    quality_of_education,
+    behaviour_attitudes,
+    personal_development,
+    leadership_management,
+    early_years_provision,
+    sixth_form_provision,
+    ungraded_outcome,
+    ungraded_grade,
+    rc_safeguarding_met,
+    rc_inclusion,
+    rc_curriculum_teaching,
+    rc_achievement,
+    rc_attendance_behaviour,
+    rc_personal_development,
+    rc_leadership_governance,
+    rc_early_years,
+    rc_sixth_form,
+    report_url
+from {{ ref('int_ofsted_latest') }}

pipeline/transform/tests/assert_ofsted_current_grade_consistent.sql

@@ -0,0 +1,10 @@
+-- A grade is dated by the inspection that awarded or confirmed it, never
+-- after the latest visit, and has a date and a basis exactly when it exists.
+-- A report card leaves no legacy grade in force.
+
+select urn
+from {{ ref('fact_ofsted_latest') }}
+where current_grade_date > latest_visit_date
+   or (current_grade is null) <> (current_grade_date is null)
+   or (current_grade is null) <> (current_grade_basis is null)
+   or (latest_visit_kind = 'report_card' and current_grade is not null)