Add Arch Linux CT support and pacman integration

Add Arch Linux container support and integrate pacman into install utilities. New files: ct/archlinux.sh (container build/update script), install/archlinux-install.sh (install entrypoint), and json/archlinux.json (metadata). misc/install.func: detect_arch in detect_os, add pacman bootstrap, and implement pacman handlers for pkg_upgrade, pkg_install, pkg_remove, pkg_clean and package refresh; include openssh install path for pacman and provide a cleanup_lxc override to run pkg_clean. Enables creating/updating Arch Linux LXC containers and proper package manager handling.

ct/archlinux.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+source <(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVED/main/misc/build.func)
+
+# Copyright (c) 2021-2026 community-scripts ORG
+# Author: MickLesk (CanbiZ)
+# License: MIT | https://github.com/community-scripts/ProxmoxVED/raw/main/LICENSE
+# Source: https://archlinux.org/
+
+APP="Arch Linux"
+var_tags="${var_tags:-os}"
+var_cpu="${var_cpu:-1}"
+var_ram="${var_ram:-512}"
+var_disk="${var_disk:-4}"
+var_os="${var_os:-archlinux}"
+var_version="${var_version:-base}"
+var_unprivileged="${var_unprivileged:-1}"
+
+header_info "$APP"
+variables
+color
+catch_errors
+
+function update_script() {
+  header_info
+  check_container_storage
+  check_container_resources
+  if [[ ! -d /var ]]; then
+    msg_error "No ${APP} Installation Found!"
+    exit
+  fi
+  msg_info "Updating Arch Linux LXC"
+  $STD pacman -Syu --noconfirm
+  msg_ok "Updated Arch Linux LXC"
+  exit
+}
+
+start
+build_container
+description
+
+msg_ok "Completed successfully!"
+msg_custom "🚀" "${GN}" "${APP} setup has been successfully initialized!"