fix(e2e): assert all-through phases via visible sub-headings, not tooltip-colliding text

The Batch E all-through journey used `#results getByText('Attainment 8').first()`,
which matched 14 nodes — mostly hidden MetricTooltip labels — so `.first()`
landed on a visibility:hidden node and `toBeVisible()` failed on staging.

Assert instead on the unique, visible all-through sub-headings
("Primary — KS2 SATs" / "Secondary — GCSEs"), which directly prove each
phase block rendered. Full suite green against staging (17/17).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0146VHeLAWjDVE2B5uU67jCB

e2e/tests/journeys.spec.ts

@@ -172,11 +172,13 @@ test('an all-through school shows BOTH its KS2 SATs and its GCSE results, not ju
   // Labelled as all-through in the hero meta.
   await expect(page.getByText(/All-through/i).first()).toBeVisible();
 
-  // The combined results section carries both phases.
+  // The combined results section carries both phases, each under its own
+  // all-through sub-heading (a unique visible node — unlike "Attainment 8",
+  // which also appears in hidden MetricTooltip labels).
   const results = page.locator('#results');
   await expect(results.getByText(/SATs & GCSE Results/)).toBeVisible();
-  await expect(results.getByText('Reading, Writing & Maths combined')).toBeVisible(); // KS2
-  await expect(results.getByText('Attainment 8').first()).toBeVisible(); // KS4
+  await expect(results.getByRole('heading', { name: /Primary.*KS2 SATs/ })).toBeVisible(); // KS2 block
+  await expect(results.getByRole('heading', { name: /Secondary.*GCSEs/ })).toBeVisible(); // KS4 block
 });
 
 test('school with no performance data still gets a working detail page', async ({ page }) => {