feat(sdlc): staging environment + automated staging→prod pipeline

- pr-checks.yml: PR gate — frontend typecheck+jest, backend import smoke,
  image builds (no push), Claude AI review posted as PR comment (severe
  findings block merge)
- deploy.yml (replaces build-and-push.yml): merge to main builds+pushes
  images tagged sha-<sha>/staging, deploys the staging Portainer stack via
  webhook, runs Playwright E2E journeys against staging, then retags the
  verified images :prod (previous kept as :prod-previous) and deploys prod
- docker-compose.portainer.staging.yml: second Portainer stack — :staging
  images, sc_staging_* names, own macvlan IPs, Airflow on 8081; data
  bootstrapped from source via the staging Airflow DAGs
- prod compose now pins :prod instead of :latest (only the promotion step
  moves it; :latest is no longer published)
- e2e/: 6 Playwright journeys (search, postcode, detail, compare, rankings)
  driven by BASE_URL — the promotion gate
- scripts/ci/ai_review.py: Claude review with structured JSON findings
- docs/DEPLOY.md: full SDLC doc incl. one-time setup checklist and rollback
- replaced removed 'next lint' with tsc typecheck; fixed stale jest tests
  (slug URLs, N/A formatting, stable trend, fake-timer setup)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PqGhF93UrpDNvXBLMjJENL

nextjs-app/__tests__/components/SchoolCard.test.tsx

@@ -34,24 +34,24 @@ describe('SchoolCard', () => {
     render(<SchoolCard school={mockSchool} />);
 
     const link = screen.getByRole('link', { name: /test primary school/i });
-    expect(link).toHaveAttribute('href', '/school/100001');
+    expect(link).toHaveAttribute('href', '/school/100001-test-primary-school');
   });
 
-  it('calls onAddToCompare when Add to Compare button is clicked', () => {
+  it('calls onAddToCompare when the Compare button is clicked', () => {
     const mockAddToCompare = jest.fn();
     render(<SchoolCard school={mockSchool} onAddToCompare={mockAddToCompare} />);
 
-    const addButton = screen.getByText('Add to Compare');
+    const addButton = screen.getByText('+ Compare');
     fireEvent.click(addButton);
 
     expect(mockAddToCompare).toHaveBeenCalledWith(mockSchool);
     expect(mockAddToCompare).toHaveBeenCalledTimes(1);
   });
 
-  it('does not render Add to Compare button when handler not provided', () => {
+  it('does not render the Compare button when handler not provided', () => {
     render(<SchoolCard school={mockSchool} />);
 
-    expect(screen.queryByText('Add to Compare')).not.toBeInTheDocument();
+    expect(screen.queryByText('+ Compare')).not.toBeInTheDocument();
   });
 
   it('displays trend indicator for positive change', () => {