feat: flake NixOS config for jupiter + VirtualBox test image

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

jupiter/hardware-configuration.nix

@@ -0,0 +1,42 @@
+# PLACEHOLDER — do not use as-is.
+#
+# Generate the real file ON the ZimaBlade after booting the NixOS installer:
+#
+#   sudo nixos-generate-config --root /mnt
+#
+# then copy /mnt/etc/nixos/hardware-configuration.nix over this file.
+# It contains machine-specific disk UUIDs, filesystems, and kernel modules.
+#
+# The block below is a minimal example so `nix flake check` does not fail on a
+# workstation. REPLACE it entirely with the generated output.
+{ config, lib, pkgs, modulesPath, ... }:
+
+{
+  imports = [ (modulesPath + "/installer/scan/not-detected.nix") ];
+
+  boot.initrd.availableKernelModules = [ "xhci_pci" "ahci" "nvme" "usbhid" "sd_mod" ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ ];
+  boot.extraModulePackages = [ ];
+
+  # Example root — replace UUID with real value from generated config.
+  fileSystems."/" = {
+    device = "/dev/disk/by-label/nixos";
+    fsType = "ext4";
+  };
+
+  fileSystems."/boot" = {
+    device = "/dev/disk/by-label/BOOT";
+    fsType = "vfat";
+  };
+
+  # Example NAS data mount. Point at your storage disk/pool.
+  # fileSystems."/mnt/data" = {
+  #   device = "/dev/disk/by-label/data";
+  #   fsType = "ext4";
+  # };
+
+  swapDevices = [ ];
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+}