feat: add run_in_all_folders script for running commands across all directories

run_in_all_folders

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+if [ "$#" -lt 1 ]; then
+  echo "Usage: run_in_all_folders command [args...]"
+  exit 1
+fi
+
+for dir in */; do
+  [ -d "$dir" ] || continue
+
+  echo "==> Running in $dir"
+
+  (
+    cd "$dir" || exit
+    "$@"
+  )
+done