feat: add football net background pattern and glass card styling

Diagonal ±45° goal-net texture on body background. All card surfaces
converted from opaque #0a1810 to glass-card (backdrop-blur + semi-transparent
rgba) or glass-card-hero (gradient rgba) so the net pattern shows through.
Covers all pages: home, groups, history, search, stats, teams, tournaments,
players, match cards, and 404.

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

app/history/page.tsx

@@ -54,8 +54,7 @@ export default function HistoryPage() {
           const topScorer = t.topScorers?.[0]
           return (
             <Link key={t.year} href={`/tournaments/${t.year}`}>
-              <div className="rounded-2xl p-5 relative overflow-hidden cursor-pointer hover:border-[rgba(34,197,94,0.3)] transition-colors"
-                style={{ background: '#0a1810', border: '1px solid rgba(34,197,94,0.13)' }}>
+              <div className="glass-card p-5 relative cursor-pointer hover:border-[rgba(34,197,94,0.3)] transition-colors">
                 {/* Year watermark */}
                 <div className="absolute right-[-6px] bottom-[-18px] font-['Bebas_Neue'] text-[88px] leading-none pointer-events-none select-none"
                   style={{ color: 'rgba(34,197,94,0.04)' }}>