refactor codebase and fix bugs

- merge dante.go and dante_control.go into single dante.go
- consolidate buildDantePacket and buildDantePacket28 into one function
- fix broken comparison logic in SetDanteClockMaster
- split ARP parsing into platform-specific files with build tags
- implement Linux ARP table parsing via /proc/net/arp
- run gofmt on all files

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

snmp.go

@@ -496,4 +496,3 @@ func (t *Tendrils) getInterfaceNames(snmp *gosnmp.GoSNMP) map[int]string {
 
 	return names
 }
-