Add inst.ks.sendmac to the iPXE boot script

Cobbler's per-MAC gPXE script passed inst.ks.sendmac, making anaconda send its
interface MACs as X-RHN-Provisioning-MAC-N headers when fetching the kickstart.
The bootapi iPXE script omitted it, so it was not a full drop-in for Cobbler's
gpxe output.

- Emit inst.ks.sendmac immediately before inst.ks= in the boot iPXE template,
  matching Cobbler ordering.

Claude-Session: https://claude.ai/code/session_01JUoARVdmhxKQHyyyp1pxeT

ipxe/boot.ipxe.tmpl

@@ -6,12 +6,14 @@ it. Mirrors how Cobbler generated a per-MAC gPXE script carrying inst.ks=.
 
 KernelURL/InitrdURL/RepoURL come from the selected catalog entry (artifactapi
 remote); KernelArgs are the catalog's extra args. KickstartURL uses
-BOOTAPI_BASE_URL (http://).
+BOOTAPI_BASE_URL (http://). inst.ks.sendmac makes anaconda send its interface
+MACs as X-RHN-Provisioning-MAC-N headers when fetching the kickstart (Cobbler
+parity; lets /ks resolve a host by MAC as well as by name).
 */ -}}
 #!ipxe
 echo bootapi: provisioning {{ .FQDN }} ({{ .Platform }})
 {{ if and .KernelURL .InitrdURL -}}
-kernel {{ .KernelURL }} initrd=initrd.img{{ if .RepoURL }} inst.repo={{ .RepoURL }}{{ end }} inst.ks={{ .KickstartURL }} ip=dhcp{{ range .KernelArgs }} {{ . }}{{ end }}
+kernel {{ .KernelURL }} initrd=initrd.img{{ if .RepoURL }} inst.repo={{ .RepoURL }}{{ end }} inst.ks.sendmac inst.ks={{ .KickstartURL }} ip=dhcp{{ range .KernelArgs }} {{ . }}{{ end }}
 initrd {{ .InitrdURL }}
 boot
 {{- else -}}