linuxPackages: 6.12 -> 6.18 (#485549)

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- Create the first release note entry in this section!

- The default kernel package has been updated from 6.12 to 6.18. All supported kernels remain available.

## New Modules {#sec-release-26.05-new-modules}

          }

        ];

        # Use LTS that bcachefs is compatible with.

        boot.kernelPackages = lib.mkDefault pkgs.linuxPackages_6_18;

        # needed for systemd-remount-fs

        system.fsPackages = [ cfg.package ];

        services.udev.packages = [ cfg.package ];

        linux_6_12_hardened = hardenedKernelFor kernels.linux_6_12 { };

        linux_hardened = hardenedKernelFor packageAliases.linux_default.kernel { };

        linux_hardened = linux_6_12_hardened;

      }

      // lib.optionalAttrs config.allowAliases {

        linux_libre = throw "linux_libre has been removed due to lack of maintenance";

  );

  packageAliases = {

    linux_default = packages.linux_6_12;

    linux_default = packages.linux_6_18;

    # Update this when adding the newest kernel major version!

    linux_latest = packages.linux_6_19;

    linux_rt_default = packages.linux_rt_5_15;