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/stats/page.tsx

@@ -51,7 +51,7 @@ function SectionTitle({ children, icon: Icon }: { children: React.ReactNode; ico
 
 function Card({ children, className = '' }: { children: React.ReactNode; className?: string }) {
   return (
-    <div className={`rounded-2xl overflow-hidden ${className}`} style={{ background: '#0a1810', border: '1px solid rgba(34,197,94,0.15)' }}>
+    <div className={`glass-card ${className}`}>
       {children}
     </div>
   )
@@ -257,7 +257,7 @@ export default function StatsPage() {
           <SectionTitle icon={SparklesIcon}>Hat-Tricks</SectionTitle>
           <div className="grid grid-cols-[repeat(auto-fill,minmax(240px,1fr))] gap-3">
             {hatTricks.map((h, i) => (
-              <div key={i} className="rounded-xl p-4" style={{ background: '#0a1810', border: '1px solid rgba(34,197,94,0.12)' }}>
+              <div key={i} className="glass-card rounded-xl p-4">
                 <div className="flex items-center gap-2 mb-2">
                   {h.team && <TeamFlag name={h.team.name} iso2={h.team.iso2} size="sm" />}
                   <div>
@@ -287,7 +287,7 @@ export default function StatsPage() {
               { label: 'Decided by PSO', value: `${etStats.wentToPenalties} (${etStats.penaltiesPct}%)` },
               { label: 'Decided in 90min', value: etStats.totalKnockoutMatches - etStats.wentToExtraTime },
             ].map(s => (
-              <div key={s.label} className="rounded-xl p-4" style={{ background: '#0a1810', border: '1px solid rgba(34,197,94,0.12)' }}>
+              <div key={s.label} className="glass-card rounded-xl p-4">
                 <div className="text-[9px] text-[#2a5c35] tracking-[0.1em] uppercase mb-2">{s.label}</div>
                 <div className="font-['Bebas_Neue'] text-2xl text-[#22c55e]">{s.value}</div>
               </div>