zram menu refactor, mesa fix & sysinfo ui

- Refactored `install_zram` into a dedicated submenu (`zram_menu`) within `modules/zram.sh`. Split monolithic logic into three distinct operations: `_zram_view`, `_zram_create`, and `_zram_remove`. Enables status verification before installation and safe cleanup. Updated main menu entry in `debianito.sh` to call the new sub-menu.
- Resolved Trixie backports dependency conflicts between `mesa-libgallium` and `mesa-va-drivers` (Mesa 26+). Modified package lists in `_helpers.sh` and `gpu.sh` to exclude `mesa-va-drivers` during backports installs, prioritizing `mesa-vulkan-drivers` for stable Gallium integration.
- Implemented dynamic dimensioning in `_show_sysinfo()`. Calculates optimal width/height based on terminal size (`tput cols`) and content length. Truncates long lines to prevent UI overflow in small terminals, capped at 22-line height.

modules/gpu/_helpers.sh

@@ -133,6 +133,14 @@ _install_mesa_backports() {
         fi
     done
 
+    # Mesa >= 25.3.3 unificó VA-API dentro de mesa-libgallium.
+    # mesa-va-drivers desde backports rompe con la nueva mesa-libgallium.
+    local _bpo_filtered=()
+    for _p in "${bpo_pkgs[@]}"; do
+        [ "$_p" != "mesa-va-drivers" ] && _bpo_filtered+=("$_p")
+    done
+    bpo_pkgs=("${_bpo_filtered[@]}")
+
     local ref_ver
     ref_ver=$(apt-cache policy mesa-vulkan-drivers 2>/dev/null | awk 'NR==3 {print $2; exit}')
     local ref_bpo_ver