Allow initrd emergency shell access on baremetal-gui

The systemd-based initrd (default here, since this host has a ZFS
root) locks the root account by default, so sulogin refuses a shell
if something in the initrd fails and it drops to emergency mode --
confirmed live: it just loops re-entering the target instead of
prompting, making an initrd-level ZFS import failure impossible to
diagnose from the console. Only affects the pre-switch-root initrd
shell, not the installed system's own login.

modules/platforms/baremetal.nix

@@ -25,4 +25,14 @@
     enable = true;
     enable32Bit = true;
   };
+
+  # The systemd-based initrd (default here since this host has a ZFS root --
+  # see modules/disko/baremetal.nix) locks the root account by default, so
+  # sulogin refuses to hand over a shell if something in the initrd (e.g.
+  # the ZFS pool import) fails and it drops to emergency mode -- confirmed
+  # live: it just loops re-entering the target instead of prompting. This
+  # only affects the pre-switch-root initrd shell, not the installed
+  # system's own login, and is worth the tradeoff on a box already reachable
+  # at the physical console.
+  boot.initrd.systemd.emergencyAccess = true;
 }