Add Python tooling validation foundation

scripts/validate-repo.sh

@@ -12,6 +12,11 @@ run_check() {
   shift
 
   printf '\n== %s ==\n' "$name"
+  if [[ ! -x "$1" ]]; then
+    printf 'WARNING: %s check is missing or not executable: %s\n' "$name" "$1"
+    return 0
+  fi
+
   if "$@"; then
     printf 'OK: %s completed\n' "$name"
   else
@@ -22,6 +27,7 @@ run_check() {
 
 run_check "Bash" "$ROOT_DIR/scripts/check-bash.sh"
 run_check "Ansible" "$ROOT_DIR/scripts/check-ansible.sh"
+run_check "Python" "$ROOT_DIR/scripts/check-python.sh"
 run_check "Docs" "$ROOT_DIR/scripts/check-docs.sh"
 
 printf '\n== Repository summary ==\n'