**Refactor OS detection and normalize Manjaro to Arch**

* Centralize OS detection and normalization in a dedicated resolver module
* Treat Manjaro consistently as Arch across dependencies and package install
* Remove duplicated OS logic and legacy lib.sh
* Rename installation entrypoint to init.sh and update Makefile accordingly

https://chatgpt.com/share/693c7b50-3be0-800f-8aeb-daf3ee929ea3

scripts/installation/os_resolver.sh

@@ -0,0 +1,82 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# -----------------------------------------------------------------------------
+# OsResolver (bash "class-style" module)
+# Centralizes OS detection + normalization + supported checks + script paths.
+# -----------------------------------------------------------------------------
+
+osr_detect_raw_id() {
+  if [[ -f /etc/os-release ]]; then
+    # shellcheck disable=SC1091
+    . /etc/os-release
+    echo "${ID:-unknown}"
+  else
+    echo "unknown"
+  fi
+}
+
+osr_detect_id_like() {
+  if [[ -f /etc/os-release ]]; then
+    # shellcheck disable=SC1091
+    . /etc/os-release
+    echo "${ID_LIKE:-}"
+  else
+    echo ""
+  fi
+}
+
+osr_normalize_id() {
+  local raw="${1:-unknown}"
+  local like="${2:-}"
+
+  # Explicit mapping first (your bugfix: manjaro -> arch everywhere)
+  case "${raw}" in
+    manjaro) echo "arch"; return 0 ;;
+  esac
+
+  # Keep direct IDs when they are already supported
+  case "${raw}" in
+    arch|debian|ubuntu|fedora|centos) echo "${raw}"; return 0 ;;
+  esac
+
+  # Fallback mapping via ID_LIKE for better portability
+  # Example: many Arch derivatives expose ID_LIKE="arch"
+  if [[ " ${like} " == *" arch "* ]]; then
+    echo "arch"; return 0
+  fi
+  if [[ " ${like} " == *" debian "* ]]; then
+    echo "debian"; return 0
+  fi
+  if [[ " ${like} " == *" fedora "* ]]; then
+    echo "fedora"; return 0
+  fi
+  if [[ " ${like} " == *" rhel "* || " ${like} " == *" centos "* ]]; then
+    echo "centos"; return 0
+  fi
+
+  echo "${raw}"
+}
+
+osr_get_os_id() {
+  local raw like
+  raw="$(osr_detect_raw_id)"
+  like="$(osr_detect_id_like)"
+  osr_normalize_id "${raw}" "${like}"
+}
+
+osr_is_supported() {
+  local id="${1:-unknown}"
+  case "${id}" in
+    arch|debian|ubuntu|fedora|centos) return 0 ;;
+    *) return 1 ;;
+  esac
+}
+
+osr_script_path_for() {
+  local script_dir="${1:?script_dir required}"
+  local os_id="${2:?os_id required}"
+  local kind="${3:?kind required}" # "dependencies" or "package"
+
+  echo "${script_dir}/${os_id}/${kind}.sh"
+}