Firefox bug fix & LXDE desktop option

- Resolved Firefox installation conflict: the "both" selection no longer triggers duplicate dialogs or cancellation; the installer now passes the resolved choice to both Mozilla and ESR installers, preserving co-installation without redundant prompts.
- Fixed bugs across Debian 11/12/13 scripts:
- Migrated `migrate.sh` to write classic `.sources` format for Debian 11 and skip the security stanza for SID.
- Corrected non-free token matching in `firmware.sh` to avoid false positives on non-free-firmware-only systems.
- Added `sudo` to `broadcom-combo.conf` creation and fixed `/etc/modprobe.d` directory handling.
- Fixed write propagation in `repos.sh` to prevent silent failures on user rejection.
- Corrected PipeWire state detection for Debian 11 and added SID security stanza exclusion.
- Added LXDE desktop environment option to `debianito.sh`:
- New "LXDE (Full)" and "LXDE Core" options in the Desktop Environment menu.
- Both options install `lightdm` in a single `apt-get install` call and enable the service via `systemctl enable`.
- Includes debconf preseed for LightDM default display manager selection.
- No extra packages, no Openbox/LXDE configuration changes.
- Added `_radiolist()` helper to `utils.sh` for safe radio-list cancellation under `set -e`.
- Added `lxde_menu()` to `desktop_display.sh` with exact 2-option radio list, single-shot dispatch, and clean `return 0` on cancel.
- Added `_install_lxde_full()` and `_install_lxde_core()` with `debconf-set-selections`, single `apt` call, and `systemctl enable lightdm` post-install.

modules/utils.sh

@@ -603,6 +603,11 @@ _checklist() {
     whiptail --title "$title" --ok-button "Apply" --checklist "$text" "$h" "$w" "$lh" "$@" 3>&1 1>&2 2>&3 || true
 }
 
+_radiolist() {
+    local title="$1" text="$2" h="$3" w="$4" lh="$5"; shift 5
+    whiptail --title "$title" --ok-button "Install" --radiolist "$text" "$h" "$w" "$lh" "$@" 3>&1 1>&2 2>&3 || true
+}
+
 _inputbox() {
     whiptail --title "$1" --ok-button "Apply" --inputbox "$2" "${3:-10}" "${4:-60}" "${5:-}" 3>&1 1>&2 2>&3 || true
 }