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.

modules/zram.sh

@@ -12,7 +12,7 @@ install_zram() {
     local half_ram_mb=$(( ((RAM_KB / 1024 / 1024 + 1) / 2) * 1024 ))
 
     local algo
-    algo=$(whiptail --title "ZRAM Compression" --menu \
+    algo=$(_menu "ZRAM Compression" \
         "ZRAM compresses a portion of RAM into compressed swap,\
  effectively increasing available memory.
 
@@ -22,8 +22,7 @@ more swap space without disk writes.
 Choose compression algorithm:" \
         $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
         "lz4"  "Fastest, low CPU (recommended)" \
-        "zstd" "Better ratio, more CPU" \
-        3>&1 1>&2 2>&3)
+        "zstd" "Better ratio, more CPU")
 
     if [ -z "$algo" ]; then
         echo "ZRAM configuration cancelled."
@@ -34,8 +33,7 @@ Choose compression algorithm:" \
     if _confirm "ZRAM Size" "Use recommended size for ZRAM? (${half_ram_mb} MB out of ${RAM_SUMMARY})"; then
         zram_size=$half_ram_mb
     else
-        zram_size=$(whiptail --title "ZRAM Size" --inputbox \
-            "Enter ZRAM size in MB:" 8 60 "$half_ram_mb" 3>&1 1>&2 2>&3)
+        zram_size=$(_inputbox "ZRAM Size" "Enter ZRAM size in MB:" 8 60 "$half_ram_mb")
         if [ -z "$zram_size" ] || ! [[ "$zram_size" =~ ^[0-9]+$ ]] || [ "$zram_size" -eq 0 ]; then
             echo "ZRAM configuration cancelled."
             return 0