Fix Mesa 32-bit dependencies on Debian 13

- Resolved critical dependency conflicts for `libgl1-mesa-dri:i386` and related Mesa libraries on Debian 13 when backports are enabled.
- Modified `_install_mesa_32bit()` in `modules/gaming/_helpers.sh` to force `-t trixie-backports` target repository for i386 packages if detected.
- Prevents version mismatch errors (Stable 25.0.7 vs Backports 26.1.2) and missing `libgbm1:i386` issues by ensuring consistent architecture resolution from the backports branch.

modules/gaming/_helpers.sh

@@ -29,7 +29,11 @@ _install_mesa_32bit() {
         return
     fi
 
-    _run_cmd "Mesa 32-bit" "sudo apt install -y ${install_list[*]}" \
+    local apt_target=""
+    if [ "$DEBIAN_VERSION" = "13" ] && [ "$(is_backports_enabled)" = "true" ]; then
+        apt_target="-t ${DEBIAN_CODENAME}-backports"
+    fi
+    _run_cmd "Mesa 32-bit" "sudo apt install -y $apt_target ${install_list[*]}" \
         "Installing Mesa drivers (${#install_list[@]} packages)..."
     echo -e "${GREEN}Mesa 32-bit libraries installed.${NC}"
 }