Apply warm editorial design system across all components

Replace generic blue/gray colors with warm editorial palette:
- Navigation: coral active states, branded logo colors
- Footer: navy background, gold section titles
- FilterBar: coral search button and focus states
- SchoolCard: coral left accent on hover, teal/coral buttons
- HomeView: gradient hero section, Playfair Display headings
- RankingsView: gold top-3 highlights, warm table styling
- ComparisonView: teal card borders, coral buttons

Consistent use of CSS variables and Playfair Display serif font
for headings throughout.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

nextjs-app/components/Footer.tsx

@@ -71,7 +71,7 @@ export function Footer() {
 
         <div className={styles.bottom}>
           <p className={styles.copyright}>
-            © {currentYear} SchoolCompare. Data © Crown copyright.
+            © {currentYear} SchoolCompare.co.uk
           </p>
           <p className={styles.disclaimer}>
             This is an unofficial service. Official school performance data is available at{' '}