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/ErrorBoundary.tsx

@@ -23,18 +23,62 @@ export class ErrorBoundary extends Component<Props, State> {
   render() {
     if (this.state.hasError && this.state.error) {
       return (
-        <div style={{ padding: "2rem", maxWidth: 900, margin: "0 auto", fontFamily: "Arial", color: "#333" }}>
-          <h1 style={{ color: "#c0392b", marginBottom: "1rem" }}>Something went wrong</h1>
-          <pre style={{ background: "#f7f7f7", padding: "1rem", overflow: "auto", fontSize: 13 }}>
-            {this.state.error.message}
-          </pre>
-          <button
-            type="button"
-            onClick={() => this.setState({ hasError: false, error: null })}
-            style={{ marginTop: "1rem", padding: "8px 16px", cursor: "pointer" }}
-          >
-            Try again
-          </button>
+        <div
+          style={{
+            minHeight: "100vh",
+            display: "flex",
+            flexDirection: "column",
+            alignItems: "center",
+            justifyContent: "center",
+            padding: "2rem",
+            fontFamily: "system-ui, -apple-system, sans-serif",
+            background: "#0c1222",
+            color: "#f1f5f9",
+            textAlign: "center",
+          }}
+        >
+          <div style={{ fontSize: "3rem", marginBottom: "1rem" }}>&#9889;</div>
+          <h1 style={{ fontSize: "1.5rem", fontWeight: 600, marginBottom: "0.75rem" }}>
+            Something went wrong
+          </h1>
+          <p style={{ color: "#94a3b8", maxWidth: 420, marginBottom: "1.5rem", lineHeight: 1.6 }}>
+            The app encountered an unexpected error. This has been logged.
+            You can try reloading the page.
+          </p>
+          <div style={{ display: "flex", gap: "12px" }}>
+            <button
+              type="button"
+              onClick={() => window.location.reload()}
+              style={{
+                padding: "10px 24px",
+                background: "#f97316",
+                color: "#fff",
+                border: "none",
+                borderRadius: "8px",
+                fontSize: "14px",
+                fontWeight: 500,
+                cursor: "pointer",
+              }}
+            >
+              Reload page
+            </button>
+            <button
+              type="button"
+              onClick={() => this.setState({ hasError: false, error: null })}
+              style={{
+                padding: "10px 24px",
+                background: "transparent",
+                color: "#94a3b8",
+                border: "1px solid #334155",
+                borderRadius: "8px",
+                fontSize: "14px",
+                fontWeight: 500,
+                cursor: "pointer",
+              }}
+            >
+              Try again
+            </button>
+          </div>
         </div>
       );
     }