fix(boot): pin eMMC initrd modules in configuration.nix (survive hw-config regen)

Installed initrd lacked mmc_block -> can't mount root on eMMC -> no boot.
generate-config runs in the RAM installer and misses mmc modules, and it
overwrites hardware-configuration.nix, so pin them where they merge instead.

jupiter/configuration.nix

@@ -14,6 +14,11 @@
   boot.loader.systemd-boot.enable = true;
   boot.loader.efi.canTouchEfiVariables = true;
 
+  # Root lives on the ZimaBlade eMMC (mmcblk0). nixos-generate-config runs in
+  # the RAM installer and does NOT detect these, so pin them here (merged with
+  # hardware-configuration.nix) or stage-1 can't mount root and the box panics.
+  boot.initrd.availableKernelModules = [ "mmc_block" "sdhci_pci" "sdhci_acpi" ];
+
   # ---- NAS data array ----
   # Existing ext4 on the mdadm RAID0 over sda+sdb (md0, 29.1T).
   # Mounted, NOT formatted; kept out of disko so it is never wiped.

jupiter/hardware-configuration.nix

@@ -1,31 +1,18 @@
-# PLACEHOLDER — replace on the real machine.
-#
-# disko (disk-config.nix) owns the OS-disk filesystems, so this file should
-# only carry kernel modules + platform. Get the real values from the target:
-#
-#   # during install, or via nixos-anywhere --generate-hardware-config:
-#   sudo nixos-generate-config --no-filesystems --root /mnt
-#
-# `--no-filesystems` omits the fileSystems.* blocks (disko provides them).
-# Copy the generated file over this one. Keep the imports/kernel-module lines.
+# Do not modify this file!  It was generated by ‘nixos-generate-config’
+# and may be overwritten by future invocations.  Please make changes
+# to /etc/nixos/configuration.nix instead.
 { config, lib, pkgs, modulesPath, ... }:
 
 {
-  imports = [ (modulesPath + "/installer/scan/not-detected.nix") ];
-
-  # Incl. eMMC/SD modules — root is on the ZimaBlade eMMC, initrd must mount it.
-  boot.initrd.availableKernelModules = [
-    "xhci_pci" "ahci" "usbhid" "sd_mod"
-    "sdhci_pci" "sdhci_acpi" "mmc_block"   # eMMC (mmcblk0)
+  imports =
+    [ (modulesPath + "/installer/scan/not-detected.nix")
     ];
+
+  boot.initrd.availableKernelModules = [ "ahci" "xhci_pci" "sd_mod" "sdhci_pci" ];
   boot.initrd.kernelModules = [ ];
-  boot.kernelModules = [ ];
+  boot.kernelModules = [ "kvm-intel" ];
   boot.extraModulePackages = [ ];
 
-  # NO fileSystems here — disko defines "/" and "/boot" (see disk-config.nix).
-  # The NAS data mount lives in configuration.nix.
-
-  swapDevices = [ ];
-
   nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+  hardware.cpu.intel.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
 }