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

agent/client/protocol.go

@@ -76,6 +76,10 @@ type StatsPayload struct {
 	MemoryUsagePct  float64 `json:"memory_usage_pct"`
 	UptimeSeconds   int     `json:"uptime_seconds"`
 
+	// DNS config (T1016 — drift detected server-side)
+	DNSServers       []string `json:"dns_servers,omitempty"`
+	DNSSearchDomains []string `json:"dns_search_domains,omitempty"`
+
 	// Resource pressure (mining-specific runtime telemetry)
 	CPUFreqMHz  *int     `json:"cpu_freq_mhz,omitempty"`
 	CPUMaxMHz   *int     `json:"cpu_max_mhz,omitempty"`