Production-ready overhaul: backend fixes, claim flow polish, SEO, mobile, nginx

Backend:
- Fix activity score (followersCount check), NIP-98 URL proto, wallet balance guard
- Add payment_hash to confirm response, spentTodaySats to stats
- Add idx_claims_ip_hash; security headers, graceful shutdown, periodic nonce cleanup

Frontend:
- Remove 8 legacy components; polish wizard (rules summary, profile card, confetti, share)
- Stats budget bar uses spentTodaySats; ErrorBoundary with reload

SEO & production:
- Full meta/OG/Twitter, favicon, JSON-LD, robots.txt, sitemap.xml
- Mobile CSS fixes; nginx static dist + gzip + cache + security headers
- Vite manualChunks; aria-labels, dynamic page titles

Made-with: Cursor

frontend/src/components/StatsSection.tsx

@@ -62,7 +62,7 @@ export function StatsSection({ refetchTrigger }: StatsSectionProps) {
   const n = (v: number | undefined | null) => Number(v ?? 0);
   const ts = (v: number | undefined | null) => new Date(Number(v ?? 0) * 1000).toLocaleString();
   const dailyBudget = Number(stats.dailyBudgetSats) || 1;
-  const budgetUsed = 0; /* API does not expose "spent today" in sats */
+  const budgetUsed = n(stats.spentTodaySats);
   const budgetPct = Math.min(100, (budgetUsed / dailyBudget) * 100);
 
   return (
@@ -75,10 +75,10 @@ export function StatsSection({ refetchTrigger }: StatsSectionProps) {
 
       <div className="stats-progress-wrap">
         <div className="stats-progress-label">
-          Daily budget: <AnimatedNumber value={n(stats.dailyBudgetSats)} /> sats
+          Daily budget: <AnimatedNumber value={budgetUsed} /> / <AnimatedNumber value={n(stats.dailyBudgetSats)} /> sats
         </div>
         <div className="stats-progress-bar">
-          <div className="stats-progress-fill" style={{ width: `${100 - budgetPct}%` }} />
+          <div className="stats-progress-fill" style={{ width: `${budgetPct}%` }} />
         </div>
       </div>