feat: add entrypoint script and healthcheck for improved container security and functionality

entrypoint.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+# This script is used as the container's entrypoint.
+# It ensures that the /app/_data directory (mounted as a volume)
+# is owned by the non-root 'appuser', so the application can write to it.
+
+set -e
+
+# Fix ownership of the data volume and execute the main command
+chown -R appuser:appgroup /app/_data
+exec su-exec appuser "$@"