feat: ✨ add ThinkPad T14 Intel Gen 6 hardware support

Add complete hardware profile for Lenovo ThinkPad T14 Intel Gen 6 with:
- Lunar Lake CPU architecture support with modern kernel requirements
- Intel Arc graphics integration
- Kernel parameters for backlight and touchpad optimization
- Fingerprint reader support with comprehensive PAM configuration guidance
- Disabled throttled service for modern Intel power management
- Updated flake.nix and README.md with new module entries

Includes detailed documentation for fingerprint authentication setup
with warnings about potential login issues and proper PAM configuration
in host systems. Follows CONTRIBUTING.md guidelines for profile structure.

lenovo/thinkpad/t14/intel/default.nix

@@ -0,0 +1,9 @@
+{ lib, pkgs, ... }:
+
+{
+  imports = [
+    ../.
+    ../../../../common/cpu/intel
+    ../../../../common/gpu/intel
+  ];
+}

lenovo/thinkpad/t14/intel/gen6/default.nix

@@ -0,0 +1,60 @@
+{
+  lib,
+  pkgs,
+  config,
+  ...
+}:
+
+{
+  imports = [
+    ../../.
+    ../../../../../common/cpu/intel/lunar-lake
+  ];
+
+  # T14 Gen 6 uses Intel Core Ultra processors (Lunar Lake architecture)
+  # with integrated Intel Arc graphics
+  # The lunar-lake module already includes appropriate GPU support
+
+  # Ensure modern kernel for full Lunar Lake support
+  boot.kernelPackages = lib.mkIf (lib.versionOlder pkgs.linux.version "6.8") pkgs.linuxPackages_latest;
+
+  # TODO: Looking for feedback on these kernel parameters for T14 Gen 6
+  # Force use of the thinkpad_acpi driver for backlight control
+  # This allows the backlight save/load systemd service to work
+  boot.kernelParams = [
+    "acpi_backlight=native"
+    # TODO: Looking for feedback - touchpad fix needed for proper click registration on some T14 models
+    "psmouse.synaptics_intertouch=0"
+  ];
+
+  # TODO: Looking for feedback - modern Intel CPUs don't typically need throttled service
+  # which can interfere with newer power management on Lunar Lake
+  services.throttled.enable = lib.mkDefault false;
+
+  # Enable fingerprint reader support
+  # NOTE: PAM configuration should be done in host config to avoid login issues
+  # See: https://github.com/NixOS/nixpkgs/issues/171136
+  services.fprintd.enable = lib.mkDefault true;
+
+  # For complete fingerprint authentication in GNOME, add the following to your host config:
+  #
+  # security.pam.services = {
+  #   # Enable fingerprint authentication for sudo
+  #   sudo.fprintAuth = lib.mkDefault true;
+  #
+  #   # Enable fingerprint authentication for su
+  #   su.fprintAuth = lib.mkDefault true;
+  #
+  #   # Enable fingerprint authentication for screen unlock
+  #   xscreensaver.fprintAuth = lib.mkDefault true;
+  #
+  #   # WARNING: login.fprintAuth may break GDM password authentication
+  #   # Only enable if you understand the risks:
+  #   # login.fprintAuth = lib.mkDefault true;
+  # };
+  #
+  # After configuration:
+  # 1. Rebuild your system
+  # 2. Enroll fingerprint: sudo fprintd-enroll $USER
+  # 3. Test sudo and screen unlock with fingerprint
+}