fix(e2e): compare-chips test must use schools in one phase

The test picked the first two /school/ links from a 'primary' search and
asserted exactly two mobile chips. But a 'primary' search can return
all-through schools (e.g. 'Hessle High School and Penshurst Primary')
that classify as secondary, so the two picks can split across phases —
the active phase then holds one school and the chips are correctly gated
out (they need ≥2 in the active phase), while the canvas still shows one
line. That's a test artefact, not a bug.

Pick three schools instead: across two phases the auto-selected majority
phase always holds ≥2, so the chip legend is guaranteed. Assert ≥2 chips
(the majority may be 2 or 3). Verified against staging.

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

e2e/tests/journeys.spec.ts

@@ -100,15 +100,20 @@ test('compare chart on mobile shows school chips with tap-to-focus', async ({ pa
     links.map((l) => (l as HTMLAnchorElement).getAttribute('href') || '')
   );
   const urns = [...new Set(hrefs.map((h) => h.match(/\/school\/(\d+)/)?.[1]).filter(Boolean))];
-  expect(urns.length).toBeGreaterThanOrEqual(2);
+  // Compare three schools, not two: a "primary" search can return all-through
+  // schools that classify as secondary, and the chips only appear for the
+  // active phase. With three schools across two phases, the auto-selected
+  // majority phase always holds ≥2, so the chip legend is guaranteed to render.
+  expect(urns.length).toBeGreaterThanOrEqual(3);
 
-  await page.goto(`/compare?urns=${urns[0]},${urns[1]}`);
+  await page.goto(`/compare?urns=${urns[0]},${urns[1]},${urns[2]}`);
   await expect(page.locator('canvas:visible').first()).toBeVisible({ timeout: 15_000 });
 
-  // The mobile chart legend renders one chip per school inside the chart card.
+  // The mobile chart legend renders one chip per school in the active phase.
   const chipGroup = page.getByRole('group', { name: /highlight a school/i });
   const chips = chipGroup.getByRole('button');
-  await expect(chips).toHaveCount(2);
+  await expect(chips.first()).toBeVisible({ timeout: 15_000 });
+  expect(await chips.count()).toBeGreaterThanOrEqual(2);
 
   // Tapping a chip focuses that school's line; tapping again releases it.
   await chips.first().click();