fix undefined values

ui/src/pages/agent.tsx

@@ -92,7 +92,7 @@ export function AgentPage() {
                                 title: "CPU USAGE",
                                 value: formatPercentage(cpuUsage),
                                 status: getMetricStatus(cpuUsage),
-                                subtitle: `${metrics?.cpu.threads} threads`,
+                                subtitle: `${metrics?.cpu.threads ?? 0} threads`,
                             }}
                         >
                             <DonutChart

ui/src/services/utils.ts

@@ -63,7 +63,7 @@ export function calcPercentage(
     value: number | undefined,
     total: number | undefined,
 ): number {
-    if (value === undefined || total === undefined) return 0;
+    if (!value || !total) return 0;
     return (value / total) * 100;
 }