chore: remove the Ofsted Parent View feature end to end

Removes the 'What Parents Say' section and all supporting elements:

Frontend:
- Drop the OfstedParentView type, the parent_view field, the survey
  section and the 'X% would recommend' callouts in the primary and
  secondary detail views, the Parents nav item, and the parent-view CSS.

Backend:
- Remove the FactParentView model, its loading in data_loader, and
  parent_view from the school-details API response.
- Bump SCHEMA_VERSION to 6 and add an idempotent drop step
  (DROP TABLE IF EXISTS marts.fact_parent_view) to the CLI migration;
  add scripts/sql/drop_fact_parent_view.sql to apply directly to the
  dbt-owned marts DBs on staging and prod.

Pipeline:
- Delete the stg_parent_view + fact_parent_view dbt models and their
  source/schema entries, the tap-uk-parent-view Meltano extractor, and
  the monthly Parent View DAG; drop it from the Dockerfile and the
  staging bootstrap docs.

The rest of dbt (which builds every mart the app reads) is untouched.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/DEPLOY.md

@@ -79,8 +79,7 @@ fail the E2E gate. That's the point: staging absorbs the risk.
 5. **Bootstrap staging data via Airflow** (no prod dump — staging populates
    itself from source, exercising the pipeline image end-to-end):
    - Open the staging Airflow UI (`http://<host>:8081`) and trigger, in order:
-     `school_data_daily`, `school_data_monthly_ofsted`,
-     `school_data_monthly_parent_view`, then the manual-schedule
+     `school_data_daily`, `school_data_monthly_ofsted`, then the manual-schedule
      `school_data_annual_ees` and `school_data_annual_idaci`.
    - First runs download from government sources (GIAS, Ofsted, EES, IDACI),
      run dbt, and sync Typesense — expect the initial backfill to take a while.