updated pxe config

docs/pxe-boot.md

@@ -11,6 +11,7 @@ The `pxe-boot` host serves HTTP boot assets for iPXE clients.
 - TFTP root for first-stage bootloaders: `/srv/pxe/tftp`
 - iPXE entry script: `/srv/pxe/http/boot.ipxe`
 - Generated iPXE menu: `/srv/pxe/http/menu.ipxe`
+- SystemRescue iPXE script: `/srv/pxe/http/systemrescue.ipxe`
 - TFTP fallback script: `/srv/pxe/tftp/autoexec.ipxe`
 - Boot binaries copied from the Nix `ipxe` package:
   - `/srv/pxe/tftp/ipxe.efi`
@@ -25,6 +26,7 @@ The host creates these directories with systemd tmpfiles:
 /srv/pxe/http
 /srv/pxe/http/images
 /srv/pxe/http/nixos
+/srv/pxe/http/systemrescue
 /srv/pxe/http/ubuntu
 /srv/pxe/http/rescue
 /srv/pxe/tftp
@@ -46,14 +48,28 @@ undionly.kpxe or ipxe.efi
 The generated menu currently exposes entries for:
 
 - NixOS installer
-- Rescue environment
+- SystemRescue environment
 - iPXE shell
 - Reboot
 
-Kernel and initrd artifacts for installer or rescue entries must be placed under
-the matching `/srv/pxe/http/<entry>/` directories by an operator or a separate
-build process. This repository defines the service and menu, not the installer
-images.
+Kernel and initrd artifacts for the NixOS installer entry must be placed under
+`/srv/pxe/http/nixos` by an operator or a separate build process.
+
+The SystemRescue entry expects the source ISO at:
+
+```text
+/srv/pxe/http/images/systemrescue.iso
+```
+
+The `stage-systemrescue.service` oneshot extracts that ISO into:
+
+```text
+/srv/pxe/http/systemrescue
+```
+
+The rescue menu entry then chains `http://192.168.2.247/systemrescue.ipxe`,
+which loads the SystemRescue kernel and initramfs from the extracted tree and
+uses `archiso_http_srv` to fetch the squashfs payload over HTTP.
 
 ## Validation
 
@@ -68,6 +84,9 @@ After deployment by an operator, basic service checks are:
 ```bash
 curl http://pxe-boot/boot.ipxe
 curl http://pxe-boot/menu.ipxe
+curl http://pxe-boot/systemrescue.ipxe
+curl -I http://pxe-boot/systemrescue/sysresccd/boot/x86_64/vmlinuz
+curl -I http://pxe-boot/systemrescue/sysresccd/boot/x86_64/sysresccd.img
 ```
 
 During a successful BIOS chainload, TFTP should deliver `undionly.kpxe` once,