feat(seo): add school name to URLs, fix sticky nav, collapse compare widget

- URLs now /school/138267-school-name instead of /school/138267
- Bare URN URLs redirect to canonical slug (backward compat)
- Remove overflow-x:hidden that broke sticky tab nav on secondary pages
- ComparisonToast starts collapsed — user must click to open

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

nextjs-app/components/SchoolCard.tsx

@@ -5,7 +5,7 @@
 
 import Link from 'next/link';
 import type { School } from '@/lib/types';
-import { formatPercentage, formatProgress, calculateTrend, getTrendColor } from '@/lib/utils';
+import { formatPercentage, formatProgress, calculateTrend, getTrendColor, schoolUrl } from '@/lib/utils';
 import styles from './SchoolCard.module.css';
 
 interface SchoolCardProps {
@@ -25,7 +25,7 @@ export function SchoolCard({ school, onAddToCompare, onRemoveFromCompare, showDi
     <div className={`${styles.card} ${isInCompare ? styles.cardInCompare : ''}`}>
       <div className={styles.header}>
         <h3 className={styles.title}>
-          <Link href={`/school/${school.urn}`}>
+          <Link href={{schoolUrl(school.urn, school.school_name)}}>
             {school.school_name}
           </Link>
         </h3>
@@ -146,7 +146,7 @@ export function SchoolCard({ school, onAddToCompare, onRemoveFromCompare, showDi
       )}
 
       <div className={styles.actions}>
-        <Link href={`/school/${school.urn}`} className="btn btn-primary">
+        <Link href={{schoolUrl(school.urn, school.school_name)}} className="btn btn-primary">
           View Details
         </Link>
         {onAddToCompare && (