Add mcp dns and mcp node routes commands

mcp dns queries MCNS via an agent to list all zones and DNS records.
mcp node routes queries mc-proxy on each node for listener/route status,
matching the mcproxyctl status output format.

New agent RPCs: ListDNSRecords, ListProxyRoutes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/agent/dns_rpc.go

@@ -0,0 +1,40 @@
+package agent
+
+import (
+	"context"
+	"fmt"
+
+	mcpv1 "git.wntrmute.dev/mc/mcp/gen/mcp/v1"
+)
+
+// ListDNSRecords queries MCNS for all zones and their records.
+func (a *Agent) ListDNSRecords(ctx context.Context, _ *mcpv1.ListDNSRecordsRequest) (*mcpv1.ListDNSRecordsResponse, error) {
+	a.Logger.Debug("ListDNSRecords called")
+
+	zones, err := a.DNS.ListZones(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("list zones: %w", err)
+	}
+
+	resp := &mcpv1.ListDNSRecordsResponse{}
+	for _, z := range zones {
+		records, err := a.DNS.ListZoneRecords(ctx, z.Name)
+		if err != nil {
+			return nil, fmt.Errorf("list records for zone %q: %w", z.Name, err)
+		}
+
+		zone := &mcpv1.DNSZone{Name: z.Name}
+		for _, r := range records {
+			zone.Records = append(zone.Records, &mcpv1.DNSRecord{
+				Id:    int64(r.ID),
+				Name:  r.Name,
+				Type:  r.Type,
+				Value: r.Value,
+				Ttl:   int32(r.TTL), //nolint:gosec // TTL is bounded
+			})
+		}
+		resp.Zones = append(resp.Zones, zone)
+	}
+
+	return resp, nil
+}