Fix empty CSP summary rendering

otel-ui/src/components/CspReportsVisualizer.tsx

@@ -183,8 +183,8 @@ export function CspReportsVisualizer() {
       <div className="grid grid-cols-2 gap-3 lg:grid-cols-4">
         <StatCard label="Reports in window" value={summary ? summary.total.toLocaleString() : "—"} />
         <StatCard label="Sites reporting" value={summary ? summary.sites.toLocaleString() : "—"} />
-        <StatCard label="Top directive" value={summary?.byDirective[0]?.name ?? "—"} />
-        <StatCard label="Top blocked host" value={summary?.byBlockedHost[0]?.name ?? "—"} />
+        <StatCard label="Top directive" value={summary?.byDirective?.[0]?.name ?? "—"} />
+        <StatCard label="Top blocked host" value={summary?.byBlockedHost?.[0]?.name ?? "—"} />
       </div>
 
       <FilterBar