New automation action that executes user scripts from a dedicated
scripts/ directory. Available as both a DO action and THEN action.
Scripts are selected from a dropdown populated by /api/scripts.
Security: only scripts in the scripts dir can run, path traversal
blocked, no shell=True, stdout/stderr capped, configurable timeout
(max 300s). Scripts receive SOULSYNC_EVENT, SOULSYNC_AUTOMATION,
and SOULSYNC_SCRIPTS_DIR environment variables.
Includes Dockerfile + docker-compose.yml changes for the scripts
volume mount, and three example scripts (hello_world.sh,
system_info.py, notify_ntfy.sh).