Keep guests running during the PVE 8 to 9 upgrade and complete the help menu

- The upgrade no longer restarts pve-manager while preparing the host, so running guests are not stopped
- The upgrade stops before touching any repository when the Proxmox VE 8 update fails or is cancelled
- The unattended mode continues into the upgrade instead of exiting after the mode question
- Without a subscription, the enterprise repository added by pve-manager 9 is left disabled after the upgrade
- grub-efi-amd64 is installed with its output visible in interactive mode
- Help menu: qm unlock and pct unlock entries in the VM/CT section, renumbered items and aligned labels
- Help menu: pvesm scan nfs takes the server address, and pveupgrade is described as the interactive upgrade
- Help menu: an empty choice no longer runs the previous command
- translate() finds catalog entries for texts with leading or trailing spaces and keeps the padding
- Spanish help menu texts use the tú form and the Intro key
- New help and upgrade messages translated into all languages

scripts/global/update-pve8.sh

@@ -188,7 +188,8 @@ EOF
         pmx_record_execution "Remove unused packages" "apt-get -y autoremove"
         apt-get -y autoremove > /dev/null 2>&1 || true
         apt-get -y autoclean > /dev/null 2>&1 || true
-        return 0
+        # Not an error, but the system was not updated.
+        return 3
     elif [[ $MENU_RESULT -eq 2 ]]; then
         msg_ok "$(translate "System is already up to date. No update needed.")"
         echo -e "\nSystem is already up to date." >> "$log_file"
@@ -280,6 +281,12 @@ EOF
         tput ed
         tput cnorm
         msg_ok "$(translate "System upgrade completed")"
+    else
+        tput rc
+        tput ed
+        tput cnorm
+        msg_error "$(translate "Proxmox VE 8 package upgrade failed. Review the APT output before retrying.")"
+        return 1
     fi