huskies: merge 568_story_gateway_ui_connected_agents_dashboard

frontend/src/api/gateway.ts

@@ -8,6 +8,8 @@ export interface JoinedAgent {
 	label: string;
 	address: string;
 	registered_at: number;
+	/// Unix timestamp of the last heartbeat from this agent.
+	last_seen: number;
 	/// Project this agent is assigned to, if any.
 	assigned_project?: string;
 }
@@ -102,4 +104,11 @@ export const gatewayApi = {
 			{ method: "DELETE" },
 		);
 	},
+
+	/// Send a heartbeat for an agent to update its last-seen timestamp.
+	heartbeat(id: string): Promise<void> {
+		return gatewayRequest<void>(`/gateway/agents/${id}/heartbeat`, {
+			method: "POST",
+		});
+	},
 };