improve ui code

ui/src/services/types.ts

@@ -44,8 +44,15 @@ export interface NetworkMetrics {
     down: number;
     up: number;
 }
+
 export interface StatusMessage {
     agent: string;
     metrics: Metrics;
     timestamp: string;
 }
+
+export interface UptimeMessage {
+    agent: string;
+    uptime: number;
+    last_seen: Date;
+}