test had no user/env/<host>/ tree because deploy/env/test/ never
existed, so `make remote-apply-env-test` hit its missing-source guard
and was silently skipped — test ran with twig cache off and without the
gzip/Content-Encoding fix, hiding the exact class of gotcha that only
surfaced in prod.
Make deploy/env/test/system.yaml a symlink to deploy/env/prod/system.yaml
so both deployed hosts share one override and can never drift; genericize
the prod file header to say it now serves test + prod.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Np4cMQLF77i664CAQXySzU
