refactor: replace remaining raw os-release checks with get_os_info helpers

- inventree: use get_os_info id for ubuntu check
- jellyfin: use get_os_info id for intel dependency path
- nginxproxymanager: use get_os_version_major for pcre package switch
- frigate: use get_os_version_major while keeping Debian 12 requirement

ct/inventree.sh

@@ -29,7 +29,7 @@ function update_script() {
     exit
   fi
 
-  if ! grep -qE "^ID=(ubuntu)$" /etc/os-release; then
+  if [[ "$(get_os_info id)" != "ubuntu" ]]; then
     msg_error "Unsupported OS. InvenTree requires Ubuntu (20.04/22.04/24.04)."
     exit
   fi

ct/jellyfin.sh

@@ -29,7 +29,7 @@ function update_script() {
     exit
   fi
 
-  if ! grep -qEi 'ubuntu' /etc/os-release; then
+  if [[ "$(get_os_info id)" != "ubuntu" ]]; then
     msg_info "Updating Intel Dependencies"
     rm -f ~/.intel-* || true
     fetch_and_deploy_gh_release "intel-igc-core-2" "intel/intel-graphics-compiler" "binary" "latest" "" "intel-igc-core-2_*_amd64.deb"

ct/nginxproxymanager.sh

@@ -55,7 +55,7 @@ function update_script() {
   fi
 
   local pcre_pkg="libpcre3-dev"
-  if grep -qE 'VERSION_ID="1[3-9]"' /etc/os-release 2>/dev/null; then
+  if [[ "$(get_os_version_major)" -ge 13 ]]; then
     pcre_pkg="libpcre2-dev"
   fi
   $STD apt install -y build-essential "$pcre_pkg" libssl-dev zlib1g-dev

install/frigate-install.sh

@@ -13,8 +13,7 @@ setting_up_container
 network_check
 update_os
 
-source /etc/os-release
-if [[ "$VERSION_ID" != "12" ]]; then
+if [[ "$(get_os_version_major)" != "12" ]]; then
   msg_error "Frigate requires Debian 12 (Bookworm) due to Python 3.11 dependencies"
   exit 238
 fi