fix: cmdTimeout type number

frontend/src/components/agent/AgentMonitor.tsx

@@ -336,7 +336,7 @@ export function AgentMonitor() {
               <Input
                 type="number"
                 value={cmdTimeout}
-                onChange={(e) => setCmdTimeout(e.target.value)}
+                onChange={(e) => setCmdTimeout(Number(e.target.value) || 30)}
                 className="h-9 bg-slate-800 border-slate-700 text-slate-200"
               />
             </div>