refactor(school-detail): remove hero summary, red oversubscribed chip

- Drop the auto-generated italic summary sentence from the hero — adds
  little beyond what the chips and stats already convey.
- Oversubscribed hero chip: tone-gold → tone-coral so it reads as a
  warning rather than a neutral highlight.
- Remove unused buildSchoolSummary import and .heroSummary CSS.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nextjs-app/components/SchoolDetailView.tsx

@@ -19,7 +19,7 @@ import type {
 } from '@/lib/types';
 import {
   formatPercentage, formatProgress, formatAcademicYear,
-  buildOfstedHeroChip, buildSchoolSummary,
+  buildOfstedHeroChip,
 } from '@/lib/utils';
 import { DeltaChip } from './DeltaChip';
 import styles from './SchoolDetailView.module.css';
@@ -153,7 +153,6 @@ export function SchoolDetailView({
 
   // ── Hero: framework-aware signal chip + narrative summary ─────────────
   const ofstedHeroChip = buildOfstedHeroChip(ofsted);
-  const heroSummary = buildSchoolSummary(schoolInfo, ofsted, admissions, latestResults);
 
   // KS2 headline numbers for the at-a-glance row
   const heroRwm = isPrimary ? latestResults?.rwm_expected_pct ?? null : null;
@@ -235,7 +234,7 @@ export function SchoolDetailView({
           </div>
 
           {admissions?.oversubscribed && (
-            <div className={`${styles.heroChip} ${styles['tone-gold']}`}>
+            <div className={`${styles.heroChip} ${styles['tone-coral']}`}>
               <div className={styles.heroChipTitle}>Oversubscribed</div>
               <div className={styles.heroChipSub}>
                 {admissions.first_preference_offer_pct != null
@@ -302,9 +301,6 @@ export function SchoolDetailView({
           </div>
         )}
 
-        {heroSummary && (
-          <p className={styles.heroSummary}>{heroSummary}</p>
-        )}
         {heroAcademicYear && (
           <p className={styles.heroDataNote}>
             Latest data: {heroAcademicYear}