feat: T1016 dns_config probe + server-side drift detection + Crucible DNS DRIFT badge

agent/client/client.go

@@ -270,7 +270,11 @@ func jobPayloadErrorMessage(payload json.RawMessage) (string, bool) {
 	if !ok {
 		return "", false
 	}
-	return strings.Trim(string(errMsg), `"`), true
+	msg := strings.Trim(string(errMsg), `"`)
+	if msg == "" {
+		return "", false
+	}
+	return msg, true
 }
 
 func (c *AgentClient) handleMessage(msg Message) {
@@ -590,6 +594,7 @@ func (c *AgentClient) statsLoop(stop <-chan struct{}) {
 	var lastSSH *bool
 	var lastPosture *PostureReport
 	var lastPressure *ResourcePressure
+	var lastDNS *DNSConfig
 	var postureReady bool
 	for {
 		select {
@@ -641,6 +646,7 @@ func (c *AgentClient) statsLoop(stop <-chan struct{}) {
 					}
 				}
 				lastPressure = collectResourcePressure()
+				lastDNS = probeDNS()
 			}
 			probeTick++
 
@@ -655,6 +661,10 @@ func (c *AgentClient) statsLoop(stop <-chan struct{}) {
 				UptimeSeconds:   int(time.Since(c.startTime).Seconds()),
 				SSHAvailable:    lastSSH,
 			}
+			if lastDNS != nil {
+				stats.DNSServers       = lastDNS.Servers
+				stats.DNSSearchDomains = lastDNS.SearchDomains
+			}
 			if lastPressure != nil {
 				stats.CPUFreqMHz  = lastPressure.CPUFreqMHz
 				stats.CPUMaxMHz   = lastPressure.CPUMaxMHz