feat(nixos): consolidate hosts into a shared flake

Manage T450s, X1EG2 and Framework 13 from pinned NixOS inputs while retaining
machine-specific storage and hardware configuration.

Changes:

Shared Configuration:
- Extract common, KDE, desktop, development and Steam modules
- Share Emacs, VS Code, htop, DevOps tools and Docker across hosts
- Remove obsolete apps and global project language runtimes

Framework:
- Import the 11th-generation Intel hardware profile
- Enable Steam and ZFS with tookland/home mounted at /home
- Document manual ext4 root and ZFS installation steps
- Require installer-generated hardware configuration before installation

Validation:
- Evaluate both ThinkPads and Framework with test hardware
- Check Nix syntax, formatting and whitespace

hosts/t450s/configuration.nix

@@ -0,0 +1,71 @@
+{ pkgs, unstable, ... }:
+
+{
+  imports = [
+    ./hardware-configuration.nix
+    ../../modules/common.nix
+    ../../modules/kde.nix
+    ../../modules/development.nix
+    ../../modules/desktop-apps.nix
+    ../../modules/gaming.nix
+  ];
+
+  boot.loader.systemd-boot.enable = true;
+  boot.loader.efi.canTouchEfiVariables = true;
+
+  boot.initrd.secrets = {
+    "/crypto_keyfile.bin" = null;
+  };
+
+  boot.initrd.luks.devices."luks-a9814d3c-ecfc-4aae-a5a9-976a55af4609".device =
+    "/dev/disk/by-uuid/a9814d3c-ecfc-4aae-a5a9-976a55af4609";
+  boot.initrd.luks.devices."luks-a9814d3c-ecfc-4aae-a5a9-976a55af4609".keyFile =
+    "/crypto_keyfile.bin";
+
+  boot.supportedFilesystems = [ "zfs" ];
+  boot.zfs.forceImportRoot = false;
+  networking.hostId = "561bd410";
+
+  boot.binfmt.registrations.appimage = {
+    wrapInterpreterInShell = false;
+    interpreter = "${pkgs.appimage-run}/bin/appimage-run";
+    recognitionType = "magic";
+    offset = 0;
+    mask = ''\xff\xff\xff\xff\x00\x00\x00\x00\xff\xff\xff'';
+    magicOrExtension = ''\x7fELF....AI\x02'';
+  };
+
+  networking.hostName = "samwise";
+
+  services.printing.drivers = [
+    pkgs.hplipWithPlugin
+    pkgs.cnijfilter2
+  ];
+
+  services.tailscale.enable = true;
+
+  hardware.sane.enable = true;
+
+  environment.systemPackages = with pkgs; [
+    unstable.android-studio
+    unstable.anytype
+    unstable.easyeffects
+    unstable.element-desktop
+    ffmpeg
+    kdePackages.kcalc
+    mailspring
+    unstable.nextcloud-client
+    unstable.onedrive
+    postman
+    unstable.threema-desktop
+    unstable.vcmi
+    wine
+    unstable.zoom-us
+  ];
+
+  services.openssh.enable = true;
+
+  networking.firewall.enable = false;
+
+  system.stateVersion = "23.05";
+}

hosts/t450s/hardware-configuration.nix

@@ -0,0 +1,42 @@
+# 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")
+    ];
+
+  boot.initrd.availableKernelModules = [ "xhci_pci" "ehci_pci" "ahci" "usbhid" "usb_storage" "sd_mod" "rtsx_pci_sdmmc" ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ "kvm-intel" ];
+  boot.extraModulePackages = [ ];
+
+  fileSystems."/" =
+    { device = "/dev/disk/by-uuid/aaa3f4d7-a3fe-42a0-ad9c-becd3bca2531";
+      fsType = "ext4";
+    };
+
+  boot.initrd.luks.devices."luks-7e29288b-0c13-4aa6-827c-7acd692f7f91".device = "/dev/disk/by-uuid/7e29288b-0c13-4aa6-827c-7acd692f7f91";
+
+  fileSystems."/boot" =
+    { device = "/dev/disk/by-uuid/1353-1FB4";
+      fsType = "vfat";
+    };
+
+  swapDevices =
+    [ { device = "/dev/disk/by-uuid/4dfd4a6e-118d-4138-9c65-be32bbf37092"; }
+    ];
+
+  # Enables DHCP on each ethernet and wireless interface. In case of scripted networking
+  # (the default) this is the recommended approach. When using systemd-networkd it's
+  # still possible to use this option, but it's recommended to use it in conjunction
+  # with explicit per-interface declarations with `networking.interfaces.<interface>.useDHCP`.
+  networking.useDHCP = lib.mkDefault true;
+  # networking.interfaces.enp0s25.useDHCP = lib.mkDefault true;
+  # networking.interfaces.wlp3s0.useDHCP = lib.mkDefault true;
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+  hardware.cpu.intel.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
+}