feat(pipeline): carry the report-card inspection's own date; pick newest MI file in discovery

The MI file's report-card grade columns belong to the latest FULL
inspection (col 'Inspection start date'), but inspection_date maps to the
legacy OEIF graded/ungraded dates — so report cards were being dated with
pre-Nov-2025 inspections. Also discover_csv_url() returned matches[0],
the oldest (2017) link on the GOV.UK page.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0146VHeLAWjDVE2B5uU67jCB

pipeline/transform/models/intermediate/int_ofsted_latest.sql

@@ -34,6 +34,7 @@ select
     rc_leadership_governance,
     rc_early_years,
     rc_sixth_form,
+    rc_inspection_date,
     report_url
 from ranked
 where rn = 1

pipeline/transform/models/marts/fact_ofsted_inspection.sql

@@ -23,5 +23,6 @@ select
     rc_leadership_governance,
     rc_early_years,
     rc_sixth_form,
+    rc_inspection_date,
     report_url
 from {{ ref('stg_ofsted_inspections') }}

pipeline/transform/models/staging/stg_ofsted_inspections.sql

@@ -49,6 +49,12 @@ renamed as (
         {{ parse_report_card_grade('rc_early_years') }}::integer          as rc_early_years,
         {{ parse_report_card_grade('rc_sixth_form') }}::integer           as rc_sixth_form,
 
+        -- Start date of the latest FULL inspection (the report-card
+        -- inspection in the renewed framework). Guarded in the final select:
+        -- only kept when the row actually carries report-card grades, because
+        -- in legacy-format files this column is the legacy inspection date.
+        to_date(nullif(trim(rc_inspection_date), 'NULL'), 'DD/MM/YYYY')   as rc_inspection_date_raw,
+
         nullif(trim(report_url), 'NULL')                                  as report_url
     from source
     where urn is not null
@@ -58,5 +64,17 @@ renamed as (
       )
 )
 
-select * from renamed
+select
+    *,
+    case
+        when rc_safeguarding_met is not null
+          or rc_inclusion is not null
+          or rc_curriculum_teaching is not null
+          or rc_achievement is not null
+          or rc_attendance_behaviour is not null
+          or rc_personal_development is not null
+          or rc_leadership_governance is not null
+        then rc_inspection_date_raw
+    end as rc_inspection_date
+from renamed
 where inspection_date is not null