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>

backend/models.py

@@ -149,29 +149,6 @@ class FactOfstedInspection(Base):
     report_url = Column(Text)
 
 
-class FactParentView(Base):
-    """Ofsted Parent View survey — latest per school."""
-    __tablename__ = "fact_parent_view"
-    __table_args__ = MARTS
-
-    urn = Column(Integer, primary_key=True)
-    survey_date = Column(Date)
-    total_responses = Column(Integer)
-    q_happy_pct = Column(Float)
-    q_safe_pct = Column(Float)
-    q_behaviour_pct = Column(Float)
-    q_bullying_pct = Column(Float)
-    q_communication_pct = Column(Float)
-    q_progress_pct = Column(Float)
-    q_teaching_pct = Column(Float)
-    q_information_pct = Column(Float)
-    q_curriculum_pct = Column(Float)
-    q_future_pct = Column(Float)
-    q_leadership_pct = Column(Float)
-    q_wellbeing_pct = Column(Float)
-    q_recommend_pct = Column(Float)
-
-
 class FactAdmissions(Base):
     """School admissions — one row per URN per year."""
     __tablename__ = "fact_admissions"