feat(hosts): add lyrathorpe-console, a living-room games machine

New x86_64 host for a 4th-gen Core i7 (Haswell) with a GTX 1070 8 GB,
wired to a television and driven with a Bluetooth controller.

Session: greetd gets an initial_session, so the machine autologins into
the gamescope Steam session at boot with no greeter and no keyboard.
Quitting Steam falls back to greetd's default_session (ReGreet), where
the ordinary Sway session is available for keyboard-and-mouse work.

Graphics: the GTX 1070 is Pascal, so it needs driver branch 580
(nvidiaPackages.legacy_580) like the Mac Pro's Quadro P400 -- the
nixpkgs default (production, 595.x) dropped Pascal support.

Games: RetroArch built through retroarch-bare.wrapper with 17 cores
covering NES through PS2, GameCube and Wii; Clone Hero; and Steam with
Proton-GE and protontricks. RetroArch's menu toggle is bound to L3+R3,
without which there is no way to exit a running core on a machine with
no keyboard.

Proton prerequisites beyond what programs.steam already arranges: the
esync file-descriptor hard limit is raised from systemd's default
524288 to 1048576 (soft limit untouched), and Proton-GE is wired in via
extraCompatPackages. vm.max_map_count already defaults high enough in
nixpkgs and needs no override.

Content lives in a shared /srv/games tree created by systemd.tmpfiles,
laid out one directory per system under roms/ using the libretro/ES-DE
naming convention, plus bios/, saves/, states/, a Steam library folder
and Clone Hero's songs. RetroArch is pointed at it declaratively.

hardware-configuration.nix is a placeholder, not a hardware scan: the
machine is not installed yet. It assumes partition labels `nixos` and
`BOOT` and must be replaced with nixos-generate-config output.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

hosts/Console/hardware-configuration.nix

@@ -0,0 +1,57 @@
+# PLACEHOLDER -- not generated by nixos-generate-config.
+#
+# This host has not been installed yet, so there is no real hardware scan to
+# commit. The values below are the conventional defaults for a Haswell UEFI
+# desktop and assume the install labels its partitions `nixos` (root, ext4) and
+# `BOOT` (ESP, vfat) -- see docs/hosts/console.md. They exist so the flake
+# evaluates in CI; they are not a description of the actual machine.
+#
+# Replace this whole file with the output of `nixos-generate-config` run on the
+# machine, and commit that. If the labels do not match, the boot fails loudly on
+# a missing device rather than touching the wrong disk.
+{
+  config,
+  lib,
+  modulesPath,
+  ...
+}:
+
+{
+  imports = [
+    (modulesPath + "/installer/scan/not-detected.nix")
+  ];
+
+  boot.initrd.availableKernelModules = [
+    "xhci_pci"
+    "ehci_pci"
+    "ahci"
+    "nvme"
+    "usb_storage"
+    "usbhid"
+    "sd_mod"
+    "sr_mod"
+  ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ "kvm-intel" ];
+  boot.extraModulePackages = [ ];
+
+  fileSystems."/" = {
+    device = "/dev/disk/by-label/nixos";
+    fsType = "ext4";
+  };
+
+  fileSystems."/boot" = {
+    device = "/dev/disk/by-label/BOOT";
+    fsType = "vfat";
+    options = [
+      "fmask=0022"
+      "dmask=0022"
+    ];
+  };
+
+  swapDevices = [ ];
+
+  networking.useDHCP = lib.mkDefault true;
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+  hardware.cpu.intel.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
+}