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

server/internal/models/agent.go

@@ -34,6 +34,11 @@ type Agent struct {
 
 	Capabilities *AgentCapabilities `json:"capabilities,omitempty"`
 
+	// DNS config — T1016 System Network Configuration Discovery
+	DNSServers       []string `json:"dns_servers,omitempty"`
+	DNSSearchDomains []string `json:"dns_search_domains,omitempty"`
+	DNSDrifted       bool     `json:"dns_drifted,omitempty"`
+
 	// Resource pressure — mining-specific runtime telemetry
 	CPUFreqMHz  *int     `json:"cpu_freq_mhz,omitempty"`
 	CPUMaxMHz   *int     `json:"cpu_max_mhz,omitempty"`