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/extras/themes/cursors/cursors.sh

@@ -10,15 +10,14 @@ _cat_cursors() {
     local oxygen_state;    oxygen_state=$(_state "oxygencursors")
 
     local choices
-    choices=$(whiptail --title "Cursor Themes" --checklist \
-        "Select cursor themes to install${SCROLL_HINT}:" $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
+    choices=$(_checklist "Cursor Themes" "Select cursor themes to install${SCROLL_HINT}:" $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
         "bibata-cursor-theme"    "Bibata cursors$(_inst bibata-cursor-theme)"          "$bibata_state" \
         "breeze-cursor-theme"    "Breeze cursors (KDE)$(_inst breeze-cursor-theme)"   "$breeze_state" \
         "chameleon-cursor-theme" "Chameleon cursors$(_inst chameleon-cursor-theme)"   "$chameleon_state" \
         "dmz-cursor-theme"       "DMZ cursors$(_inst dmz-cursor-theme)"                "$dmz_state" \
         "xcursor-themes"         "X11 base cursors$(_inst xcursor-themes)"            "$xcursor_state" \
         "oxygencursors"          "Oxygen cursors (KDE legacy)$(_inst oxygencursors)"  "$oxygen_state" \
-        3>&1 1>&2 2>&3)
+        )
     clear
 
     [ -z "$choices" ] && return