diff --git a/misc/tools.func b/misc/tools.func
index c4a70e81f..a9a385cdd 100644
--- a/misc/tools.func
+++ b/misc/tools.func
@@ -205,6 +205,54 @@ should_upgrade() {
   return 1
 }
 
+# ------------------------------------------------------------------------------
+# Get OS information (cached for performance)
+# ------------------------------------------------------------------------------
+get_os_info() {
+  local field="${1:-all}" # id, codename, version, version_id, all
+
+  # Cache OS info to avoid repeated file reads
+  if [[ -z "${_OS_ID:-}" ]]; then
+    export _OS_ID=$(awk -F= '/^ID=/{gsub(/"/,"",$2); print $2}' /etc/os-release)
+    export _OS_CODENAME=$(awk -F= '/^VERSION_CODENAME=/{gsub(/"/,"",$2); print $2}' /etc/os-release)
+    export _OS_VERSION=$(awk -F= '/^VERSION_ID=/{gsub(/"/,"",$2); print $2}' /etc/os-release)
+    export _OS_VERSION_FULL=$(awk -F= '/^VERSION=/{gsub(/"/,"",$2); print $2}' /etc/os-release)
+  fi
+
+  case "$field" in
+  id) echo "$_OS_ID" ;;
+  codename) echo "$_OS_CODENAME" ;;
+  version) echo "$_OS_VERSION" ;;
+  version_id) echo "$_OS_VERSION" ;;
+  version_full) echo "$_OS_VERSION_FULL" ;;
+  all) echo "ID=$_OS_ID CODENAME=$_OS_CODENAME VERSION=$_OS_VERSION" ;;
+  *) echo "$_OS_ID" ;;
+  esac
+}
+
+# ------------------------------------------------------------------------------
+# Check if running on specific OS
+# ------------------------------------------------------------------------------
+is_debian() {
+  [[ "$(get_os_info id)" == "debian" ]]
+}
+
+is_ubuntu() {
+  [[ "$(get_os_info id)" == "ubuntu" ]]
+}
+
+is_alpine() {
+  [[ "$(get_os_info id)" == "alpine" ]]
+}
+
+# ------------------------------------------------------------------------------
+# Get Debian/Ubuntu major version
+# ------------------------------------------------------------------------------
+get_os_version_major() {
+  local version=$(get_os_info version)
+  echo "${version%%.*}"
+}
+
 # ------------------------------------------------------------------------------
 # Download file with retry logic and progress
 # ------------------------------------------------------------------------------
@@ -233,7 +281,7 @@ download_file() {
 }
 
 # ------------------------------------------------------------------------------
-# Get fallback suite for repository
+# Get fallback suite for repository (comprehensive mapping)
 # ------------------------------------------------------------------------------
 get_fallback_suite() {
   local distro_id="$1"
@@ -246,18 +294,54 @@ get_fallback_suite() {
     return 0
   fi
 
-  # Fallback mappings
+  # Comprehensive fallback mappings
   case "$distro_id" in
   debian)
     case "$distro_codename" in
-    trixie | forky) echo "bookworm" ;;
-    *) echo "bookworm" ;;
+    # Debian 13 (Trixie) → Debian 12 (Bookworm)
+    trixie | forky | sid)
+      echo "bookworm"
+      ;;
+    # Debian 12 (Bookworm) stays
+    bookworm)
+      echo "bookworm"
+      ;;
+    # Debian 11 (Bullseye) stays
+    bullseye)
+      echo "bullseye"
+      ;;
+    # Unknown → latest stable
+    *)
+      echo "bookworm"
+      ;;
     esac
     ;;
   ubuntu)
     case "$distro_codename" in
-    oracular | noble | mantic) echo "jammy" ;;
-    *) echo "jammy" ;;
+    # Ubuntu 24.10 (Oracular) → 24.04 LTS (Noble)
+    oracular | plucky)
+      echo "noble"
+      ;;
+    # Ubuntu 24.04 LTS (Noble) stays
+    noble)
+      echo "noble"
+      ;;
+    # Ubuntu 23.10 (Mantic) → 22.04 LTS (Jammy)
+    mantic | lunar)
+      echo "jammy"
+      ;;
+    # Ubuntu 22.04 LTS (Jammy) stays
+    jammy)
+      echo "jammy"
+      ;;
+    # Ubuntu 20.04 LTS (Focal) stays
+    focal)
+      echo "focal"
+      ;;
+    # Unknown → latest LTS
+    *)
+      echo "jammy"
+      ;;
     esac
     ;;
   *)
@@ -279,6 +363,148 @@ verify_package_source() {
   return 1
 }
 
+# ------------------------------------------------------------------------------
+# Check if running on LTS version
+# ------------------------------------------------------------------------------
+is_lts_version() {
+  local os_id=$(get_os_info id)
+  local codename=$(get_os_info codename)
+
+  if [[ "$os_id" == "ubuntu" ]]; then
+    case "$codename" in
+    focal | jammy | noble) return 0 ;; # 20.04, 22.04, 24.04
+    *) return 1 ;;
+    esac
+  elif [[ "$os_id" == "debian" ]]; then
+    # Debian releases are all "stable"
+    case "$codename" in
+    bullseye | bookworm | trixie) return 0 ;;
+    *) return 1 ;;
+    esac
+  fi
+
+  return 1
+}
+
+# ------------------------------------------------------------------------------
+# Get optimal number of parallel jobs (cached)
+# ------------------------------------------------------------------------------
+get_parallel_jobs() {
+  if [[ -z "${_PARALLEL_JOBS:-}" ]]; then
+    local cpu_count=$(nproc 2>/dev/null || echo 1)
+    local mem_gb=$(free -g | awk '/^Mem:/{print $2}')
+
+    # Limit by available memory (assume 1GB per job for compilation)
+    local max_by_mem=$((mem_gb > 0 ? mem_gb : 1))
+    local max_jobs=$((cpu_count < max_by_mem ? cpu_count : max_by_mem))
+
+    # At least 1, at most cpu_count
+    export _PARALLEL_JOBS=$((max_jobs > 0 ? max_jobs : 1))
+  fi
+  echo "$_PARALLEL_JOBS"
+}
+
+# ------------------------------------------------------------------------------
+# Get default PHP version for OS
+# ------------------------------------------------------------------------------
+get_default_php_version() {
+  local os_id=$(get_os_info id)
+  local os_version=$(get_os_version_major)
+
+  case "$os_id" in
+  debian)
+    case "$os_version" in
+    13) echo "8.3" ;; # Debian 13 (Trixie)
+    12) echo "8.2" ;; # Debian 12 (Bookworm)
+    11) echo "7.4" ;; # Debian 11 (Bullseye)
+    *) echo "8.2" ;;
+    esac
+    ;;
+  ubuntu)
+    case "$os_version" in
+    24) echo "8.3" ;; # Ubuntu 24.04 LTS (Noble)
+    22) echo "8.1" ;; # Ubuntu 22.04 LTS (Jammy)
+    20) echo "7.4" ;; # Ubuntu 20.04 LTS (Focal)
+    *) echo "8.1" ;;
+    esac
+    ;;
+  *)
+    echo "8.2"
+    ;;
+  esac
+}
+
+# ------------------------------------------------------------------------------
+# Get default Python version for OS
+# ------------------------------------------------------------------------------
+get_default_python_version() {
+  local os_id=$(get_os_info id)
+  local os_version=$(get_os_version_major)
+
+  case "$os_id" in
+  debian)
+    case "$os_version" in
+    13) echo "3.12" ;; # Debian 13 (Trixie)
+    12) echo "3.11" ;; # Debian 12 (Bookworm)
+    11) echo "3.9" ;;  # Debian 11 (Bullseye)
+    *) echo "3.11" ;;
+    esac
+    ;;
+  ubuntu)
+    case "$os_version" in
+    24) echo "3.12" ;; # Ubuntu 24.04 LTS
+    22) echo "3.10" ;; # Ubuntu 22.04 LTS
+    20) echo "3.8" ;;  # Ubuntu 20.04 LTS
+    *) echo "3.10" ;;
+    esac
+    ;;
+  *)
+    echo "3.11"
+    ;;
+  esac
+}
+
+# ------------------------------------------------------------------------------
+# Get default Node.js LTS version
+# ------------------------------------------------------------------------------
+get_default_nodejs_version() {
+  # Always return current LTS (as of 2025)
+  echo "20"
+}
+
+# ------------------------------------------------------------------------------
+# Check if package manager is locked
+# ------------------------------------------------------------------------------
+is_apt_locked() {
+  if fuser /var/lib/dpkg/lock-frontend &>/dev/null ||
+    fuser /var/lib/apt/lists/lock &>/dev/null ||
+    fuser /var/cache/apt/archives/lock &>/dev/null; then
+    return 0
+  fi
+  return 1
+}
+
+# ------------------------------------------------------------------------------
+# Wait for apt to be available
+# ------------------------------------------------------------------------------
+wait_for_apt() {
+  local max_wait="${1:-300}" # 5 minutes default
+  local waited=0
+
+  while is_apt_locked; do
+    if [[ $waited -ge $max_wait ]]; then
+      msg_error "Timeout waiting for apt to be available"
+      return 1
+    fi
+
+    debug_log "Waiting for apt to be available... (${waited}s)"
+    sleep 5
+    waited=$((waited + 5))
+  done
+
+  return 0
+}
+
 # ------------------------------------------------------------------------------
 # Cleanup old repository files (migration helper)
 # ------------------------------------------------------------------------------