fix(ofsted): apply ungraded fallback on school detail page too

The detail page reads overall_effectiveness from the API and showed
"Not rated" for ungraded-only schools, even though the list badge uses
the coalesced grade. Coalesce the ungraded fallback into the API's
overall_effectiveness so the detail page shows the same grade.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/data_loader.py

@@ -416,7 +416,14 @@ def get_supplementary_data(db: Session, urn: int) -> dict:
             "framework": o.framework,
             "inspection_date": o.inspection_date.isoformat() if o.inspection_date else None,
             "inspection_type": o.inspection_type,
-            "overall_effectiveness": o.overall_effectiveness,
+            # Fall back to the grade parsed from an ungraded (Section 8) outcome
+            # (e.g. "School remains Good") when there's no graded grade, so the
+            # detail page matches the list badge.
+            "overall_effectiveness": (
+                o.overall_effectiveness
+                if o.overall_effectiveness is not None
+                else o.ungraded_grade
+            ),
             "quality_of_education": o.quality_of_education,
             "behaviour_attitudes": o.behaviour_attitudes,
             "personal_development": o.personal_development,