Same two scoped changes as PR #15's rebase, now applied on a branch cut
from TODAY's main so the merge base is current (PR #15 became
unmergeable — its 09-03 merge base predated main's heavy hand-edits):
1. ai) case -> `python3 deploy/provision-stack.py ai` (one line). Retires
main's heredoc with its live drift: AI_LITELLM_POSTGRES_PASSWORD
printed twice (one copy from retired AI_LITELLM_DB_PASSWORD), stray
legacy AI_WEBUI_SECRET_KEY, and the WEB_UI/WEBUI shell-var mismatch
that renders an EMPTY OAuth client secret into ai.env.
2. env block ai section: normalized to exact template placeholder names,
added AI_MCPO_API_KEY (NEW Woodpecker secret required pre-merge),
pruned now-template-literal vars.
apk gains python3 py3-yaml. Everything else byte-matches current main.
Dollar-escape audit done per header lesson.