refactor(detail): extract sections as server components

Moves ~1,300 lines of section markup out of the two client views into
components/school/, mirroring the components/compare/ layout. Twelve section
components plus shared primitives, all server components. The only client
file is AdmissionsViewToggle, which owns the hidden/aria-pressed state and
receives both views as server-rendered children.

JSX was extracted mechanically rather than retyped, so the markup the CSS
modules depend on is verbatim.

Sharing follows measured similarity, not assumption:
- Finances (91%) shared. The secondary premises-cost card is gated behind a
  prop so primary pages are unchanged; enabling it is a one-line follow-up.
- Ofsted (80%) shared, but behind a variant prop. The headline similarity hid
  a real fork: on a school with no overall grade the primary page shows a
  "Not rated" badge while the secondary shows a four-area OEIF panel, and the
  disclaimer copy differs. Both preserved exactly; reconciling them is a
  human decision, not a side effect of a move.
- Admissions (14%) and History (40%) kept separate.

Not yet wired up -- the old views still render.

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

nextjs-app/components/school/SecondaryHistorySection.tsx

@@ -0,0 +1,74 @@
+/**
+ * SecondaryHistorySection — results over time. Secondary pages.
+ * Server component.
+ */
+
+import dynamic from 'next/dynamic';
+import type { School, SchoolResult, NationalAverages } from '@/lib/types';
+import { formatPercentage, formatProgress, formatAcademicYear } from '@/lib/utils';
+import { Section, sectionStyles as styles } from './sectionShared';
+
+const PerformanceChart = dynamic(
+  () => import('../PerformanceChart').then((m) => m.PerformanceChart),
+  { ssr: false },
+);
+
+export function SecondaryHistorySection({
+  yearlyData, schoolInfo, nationalAvg, secondaryAvg, suppressComparison,
+}: {
+  yearlyData: SchoolResult[];
+  schoolInfo: School;
+  nationalAvg: NationalAverages | null;
+  secondaryAvg: Record<string, number>;
+  suppressComparison: boolean;
+}) {
+  // National Attainment 8 baseline for the "Results Over Time" chart.
+  const heroAtt8Nat = secondaryAvg.attainment_8_score ?? null;
+
+  return (
+    <section id="history" className={styles.card}>
+      <h2 className={styles.sectionTitle}>Historical Results</h2>
+      {yearlyData.length > 0 && (
+        <>
+          <h3 className={styles.subSectionTitle} style={{ marginTop: '1.25rem' }}>Results Over Time</h3>
+          <div className={styles.chartContainer}>
+            <PerformanceChart
+              data={yearlyData}
+              schoolName={schoolInfo.school_name}
+              isSecondary={true}
+              nationalAtt8Avg={suppressComparison ? null : heroAtt8Nat}
+              nationalByYear={suppressComparison ? undefined : nationalAvg?.by_year}
+            />
+          </div>
+        </>
+      )}
+      <details className={styles.historyDisclosure}>
+        <summary className={styles.historyToggle}>View raw year-by-year data</summary>
+        <div className={styles.tableWrapper}>
+          <table className={styles.dataTable}>
+            <thead>
+              <tr>
+                <th>Year</th>
+                <th>Attainment 8</th>
+                <th>Progress 8</th>
+                <th>Eng &amp; Maths 4+</th>
+                <th>EBacc entry %</th>
+              </tr>
+            </thead>
+            <tbody>
+              {yearlyData.map((result) => (
+                <tr key={result.year}>
+                  <td className={styles.yearCell}>{formatAcademicYear(result.year)}</td>
+                  <td>{result.attainment_8_score != null ? result.attainment_8_score.toFixed(1) : '-'}</td>
+                  <td>{result.progress_8_score != null ? formatProgress(result.progress_8_score) : '-'}</td>
+                  <td>{result.english_maths_standard_pass_pct != null ? formatPercentage(result.english_maths_standard_pass_pct) : '-'}</td>
+                  <td>{result.ebacc_entry_pct != null ? formatPercentage(result.ebacc_entry_pct) : '-'}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      </details>
+    </section>
+  );
+}