label OCI manager Apps as a Technology Preview, as Proxmox VE does

- OCI manager Apps carries the Technology Preview label that Proxmox VE gives to application containers from OCI images, in the main menu, the engine windows, the menu search, the message at the end of each installation, the release notes and the documentation.
- The documentation explains that the label refers to the Proxmox VE support it runs on, not to the ProxMenux engine, and stays until Proxmox VE marks it as stable.
- Spanish for the new message; the other languages are left to the translation bot.

scripts/oci/oci_manager_apps.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 # ==========================================================
-# ProxMenux - OCI manager Apps (beta)
+# ProxMenux - OCI manager Apps (Technology Preview)
 # ==========================================================
 # Author      : MacRimi
 # Copyright   : (c) 2024 MacRimi
@@ -37,7 +37,7 @@ ensure_oci_dependencies() {
     [[ ${#missing[@]} -eq 0 ]] && return 0
 
     show_proxmenux_logo
-    msg_title "$(translate "OCI manager Apps (beta)")"
+    msg_title "$(translate "OCI manager Apps (Technology Preview)")"
     msg_info "$(translate "Installing required packages...")"
     apt-get update >/dev/null 2>&1
     local status
@@ -56,6 +56,31 @@ ensure_oci_dependencies() {
     stop_spinner
 }
 
+# Proxmox VE runs OCI images as LXC containers from 9.1 on.
+pve_supports_oci() {
+    local version major minor
+    version=$(pveversion 2>/dev/null | grep -oP 'pve-manager/\K[0-9]+\.[0-9]+' | head -1)
+    major=${version%%.*}
+    minor=${version#*.}
+    [[ $major =~ ^[0-9]+$ && $minor =~ ^[0-9]+$ ]] || return 1
+    (( major > 9 || (major == 9 && minor >= 1) ))
+}
+
+if ! pve_supports_oci; then
+    show_proxmenux_logo
+    msg_title "$(translate "OCI manager Apps (Technology Preview)")"
+    msg_error "$(translate "OCI containers require Proxmox VE 9.1 or later.")"
+    PVE_VERSION=$(pveversion 2>/dev/null | grep -oP 'pve-manager/\K[0-9.]+' | head -1)
+    [[ -n $PVE_VERSION ]] && msg_info2 "$(translate "Current version:") $PVE_VERSION"
+    if [[ -t 0 ]]; then
+        echo
+        msg_success "$(translate "Press Enter to return to the menu...")"
+        read -r
+        [[ $# -eq 0 ]] && exec bash "$LOCAL_SCRIPTS/menus/main_menu.sh"
+    fi
+    exit 1
+fi
+
 if [[ ! -f "$OCI_ENGINE_DIR/src/proxmenux_oci/__main__.py" ]]; then
     msg_error "$(translate "The OCI engine is not installed. Update ProxMenux and try again.")"
     exit 1