Replace hardcoded paths with constants

Added path constant for disk-by-path location:
  DISK_BY_PATH="/dev/disk/by-path"

Updated build_drive_map() to use the constant instead of
hardcoded path strings.

Note: LOG_DIR not added as the script does not currently use
logging to files. Can be added if logging feature is implemented.

Fixes: #24

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

driveAtlas.sh

@@ -13,6 +13,12 @@ set -o pipefail
 
 VERSION="1.1.0"
 
+#------------------------------------------------------------------------------
+# Path Constants
+# Centralized path definitions to avoid hardcoding throughout the script
+#------------------------------------------------------------------------------
+readonly DISK_BY_PATH="/dev/disk/by-path"
+
 #------------------------------------------------------------------------------
 # show_usage
 #
@@ -619,8 +625,8 @@ build_drive_map() {
         [[ -z "$path" || -z "$slot" ]] && continue
 
         BAY_TO_PCI_PATH[$slot]="$path"
-        if [[ -L "/dev/disk/by-path/$path" ]]; then
-            local drive="$(readlink -f "/dev/disk/by-path/$path" | sed 's/.*\///')"
+        if [[ -L "${DISK_BY_PATH}/$path" ]]; then
+            local drive="$(readlink -f "${DISK_BY_PATH}/$path" | sed 's/.*\///')"
             DRIVE_MAP[$slot]="$drive"
             ((mapped_count++))
         else