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/system/audio.sh

@@ -9,7 +9,11 @@ _prefs_audio_menu() {
 
     local pw_label="PipeWire Audio Stack (Bluetooth Hi-Res)"
 
-    local pw_state; pw_state=$(_state "pipewire-audio")
+    # Bullseye ships the "pipewire" package; the pipewire-audio meta-package
+    # only exists from Bookworm onwards
+    local pw_pkg="pipewire-audio"
+    [ "$DEBIAN_VERSION" = "11" ] && pw_pkg="pipewire"
+    local pw_state; pw_state=$(_state "$pw_pkg")
     items+=(
         "pipewire-audio" "$pw_label" "$pw_state"
     )