Without this, Windows Docker Desktop checks out the entrypoint and
helper scripts with CRLF, and `#!/bin/sh\r` either fails outright or
silently exec's the wrong interpreter, depending on the kernel +
busybox combo.
Adds .gitattributes to pin LF on all shell/Python/YAML files +
renormalises the existing entrypoint.sh.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
