Migrated desktop environment from XFCE to KDE Plasma with simplified profiles.

- Replaced XFCE with KDE Plasma and SDDM display manager.
- Reduced profiles from seven to four (minimal, server, basic, office).
- Split home skeleton files into home-skel and home-skel-desktop directories.
- Added display name prompt during user setup.
- Added 7zip and fwupd to base packages.

lib/desktop/kde.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# kde.sh - KDE Plasma desktop environment installation
+#
+# Installs KDE Plasma with SDDM display manager.
+# KDE_PACKAGES is defined in config/profiles.conf.
+
+# Install KDE base packages
+install_kde_packages() {
+    chroot_pacman_install "${KDE_PACKAGES[@]}"
+}
+
+# Copy desktop skeleton files to user home
+# Arguments:
+#   $1 - username
+copy_desktop_skel() {
+    local username="$1"
+    local home_dir="${MOUNT_POINT}/home/${username}"
+
+    cp -r "${HOME_SKEL_DESKTOP_DIR}/." "${home_dir}/"
+    rm -f "${home_dir}/.gitkeep"
+    chown -R 1000:1000 "${home_dir}"
+}
+
+# Full KDE installation
+# Arguments:
+#   $1 - username
+install_kde() {
+    local username="$1"
+
+    install_kde_packages
+    chroot_systemd_enable sddm.service
+    copy_desktop_skel "$username"
+    chroot_run usermod -aG wireshark "$username"
+}