refactor to per-node snmp polling and immediate arp dump

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tendrils.go

@@ -48,11 +48,9 @@ func (t *Tendrils) Run() {
 	t.populateLocalAddresses()
 
 	if !t.DisableARP {
+		t.readARPTable()
 		go t.pollARP(ctx)
 	}
-	if !t.DisableSNMP {
-		go t.pollSNMP(ctx)
-	}
 
 	ticker := time.NewTicker(1 * time.Second)
 	defer ticker.Stop()