v2.1.1 - fix CLI env updates + SSH env visibility

Fixes:
- Generated CLI flag handlers (--port, --memory, --cpus, etc.)
  now work on upgraded installs where .env is missing new keys.
  Replaced sed "s/^KEY=.*/KEY=val/" with set_env() delete+append.

Features:
- Container env vars dumped to /etc/environment so SSH sessions
  can access them.

102 integration tests passing.