critical-fixes, swap module & gaming overhaul

- Fixed script crashes from `whiptail` Cancel/Esc under `set -e`. Added `_menu()`, `_checklist()` and `_inputbox()` wrappers with `|| true` to prevent premature exits.
- Resolved startup failures by using defaults instead of relying on unset variables with `set -u`.
- Hardened sudoers management — `_validate_sudoers()` writes to temp file, validates with `visudo -cf`, only copies if successful.
- Replaced `eval` in `_run_cmd` with safer `bash -c` execution.

Swap Management Module (`modules/swap.sh`)
- New standalone module with 9 internal functions and `manage_swap()` entry point.
- Btrfs CoW detection — applies `chattr +C` before swapfile creation to prevent mkswap rejection on Btrfs.
- Dynamic swappiness configuration — reads current system value instead of hardcoding 60, pre-fills inputbox with existing setting.
- Uses `/run/lock/debianito-swap.lock` for early init compatibility (added as option 9 in main menu).

Repository & Branch Migration (`modules/repos/migrate.sh`)
- Handles branch migration from stable (11/12) to Testing or SID with 5-screen UX flow.
- Persistent backup system — creates timestamped tar.gz backups of `/etc/apt/sources.list*`, auto-restores on apt update failure.
- SID guardrails — installs `apt-listbugs` and `apt-listchanges` before upgrade to warn about critical bugs in unstable packages.
- Dynamic menu options based on Debian version (SID shows only 1-2-3 Exit, non-SID includes backports + branch migration).
- New `_components_enabled()` helper detects current contrib/non-free state.

Gaming Module Overhaul
- Unified gaming checklist — merged i386 toggle into single prompt with lazy evaluation instead of separate pre-check.
- Lazy 32-bit architecture enablement — only enables i386 when needed (steam/lutris/i386 selected) and installs graphics drivers if `need_32bit=true`.
- New `_install_nvidia_32bit()` helper with proper driver detection, version pinning, and legacy/tesla variant handling.

Heroic & OpenRGB Downloads
- Heroic — fetches latest release from GitHub API using `jq` to extract amd64.deb URL, validates with `dpkg-deb --info`.
- OpenRGB — downloads from Codeberg Gitea API with SHA256 verification when available, fallback to `dpkg-deb` validation.
- Dynamic codename detection — now detects Bookworm vs Trixie at runtime instead of hardcoded static values for .deb download URLs.

|Other Improvements
- Renumbered main menu: 8=ZRAM, 9=Swap Management, 10=Extras, 11=Boot Rescue, 12=Exit.
- Improved `detect_storage()` — excludes loop/CD-ROM devices via `lsblk -e 7,11`, explicitly skips zram, detects USB/SD via `/sys/block/$name/removable`.
- Standardized SCROLL_HINT across all files with centralized readonly variable.

debianito.sh

@@ -29,6 +29,7 @@ source "${MODULES_DIR}/repos.sh"
 [ -f "${MODULES_DIR}/zram.sh" ]      && source "${MODULES_DIR}/zram.sh"
 [ -f "${MODULES_DIR}/extras/java.sh" ] && source "${MODULES_DIR}/extras/java.sh"
 [ -f "${MODULES_DIR}/rescue.sh" ]    && source "${MODULES_DIR}/rescue.sh"
+[ -f "${MODULES_DIR}/swap.sh" ]     && source "${MODULES_DIR}/swap.sh"
 
 # ── Bullseye-specific modules (loaded only on Debian 11) ──
 if [ -d "${MODULES_DIR}/bullseye" ]; then
@@ -43,7 +44,7 @@ DEBIAN_CODENAME=""
 
 main_menu() {
     # Auto-adjust TUI dimensions for small terminals
-    if [ "$LINES" -lt $((TUI_ALTO + 6)) ] || [ "$COLUMNS" -lt $((TUI_ANCHO + 6)) ]; then
+    if [ "${LINES:-24}" -lt $((TUI_ALTO + 6)) ] || [ "${COLUMNS:-80}" -lt $((TUI_ANCHO + 6)) ]; then
         TUI_ALTO=$((LINES - 4 > 8 ? LINES - 4 : 8))
         TUI_ANCHO=$((COLUMNS - 4 > 50 ? COLUMNS - 4 : 50))
         TUI_ALTO_LISTA=$((TUI_ALTO - 10 > 4 ? TUI_ALTO - 10 : 4))
@@ -51,7 +52,7 @@ main_menu() {
 
     while true; do
         local choice
-        choice=$(whiptail --title "DEBIANITO — simple configurator script" --menu "" \
+        choice=$(_menu "DEBIANITO — simple configurator script" "" \
             $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
             "1" "System Info" \
             "2" "User Privileges & Feedback" \
@@ -60,11 +61,11 @@ main_menu() {
             "5" "Graphics Drivers & Mesa Stack" \
             "6" "Backports Kernel" \
             "7" "Gaming Setup" \
-            "8" "ZRAM (Swap)" \
-            "9" "Install Programs and Software" \
-            "10" "Boot Rescue & Repair" \
-            "11" "Exit" \
-            3>&1 1>&2 2>&3)
+            "8" "ZRAM" \
+            "9" "Swap Management" \
+            "10" "Install Programs and Software" \
+            "11" "Boot Rescue & Repair" \
+            "12" "Exit")
 
         clear
 
@@ -104,15 +105,16 @@ kernels. Use the stable kernel provided by Bullseye." 10 60
                 fi
                 ;;
             8)  install_zram || true ;;
-            9)
+            9)  manage_swap || true ;;
+            10)
                 if [ "$DEBIAN_VERSION" = "11" ] && type install_extras_bullseye &>/dev/null; then
                     install_extras_bullseye || true
                 else
                     install_extras || true
                 fi
                 ;;
-            10) rescue_boot || true ;;
-            11) echo "Exiting."; exit 0 ;;
+            11) rescue_boot || true ;;
+            12) echo "Exiting."; exit 0 ;;
         esac
     done
 }