Improve: Better script vs. source context detection in menu-functions.sh

IMPROVEMENTS:
- Line 20-27: Replace 'return || exit' pattern with explicit context check
- Uses BASH_SOURCE check to determine if running as script or sourced
- Clearer intent: exit for scripts, return for sourced libraries

Rationale: 'return 2>/dev/null || exit' works but is confusing.
Explicit 'if' with BASH_SOURCE check is clearer and more maintainable.

RESULTS:
- Library behavior more explicit and easier to understand
- Better error handling for version mismatches

lib/menu-functions.sh

@@ -20,7 +20,11 @@ set -eo pipefail
 # Bash version check
 if [ "${BASH_VERSINFO[0]}" -lt 4 ] || ([ "${BASH_VERSINFO[0]}" -eq 4 ] && [ "${BASH_VERSINFO[1]}" -lt 1 ]); then
     echo "[ERROR] menu-functions.sh requires Bash 4.1 or later (detected: ${BASH_VERSION})" >&2
-    return 1 2>/dev/null || exit 1
+    if [ "${BASH_SOURCE[0]}" = "${0}" ]; then
+        exit 1
+    else
+        return 1
+    fi
 fi
 
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