Add a VERSION file (0.1.0) and inject APP_VERSION/GIT_SHA/BUILD_DATE as Docker
build-args (both stages; Vite inlines them into the SPA). New public GET
/api/version returns app_version, git_sha, build_date and the Alembic head as the
database revision. deploy.sh and the localdev build pass the args.
Drop docs/deployment-plan.md (internal planning doc, kept out of the repo) and
replace the personal lab DB IP and host names in the env/compose/deploy docs with
generic placeholders, so the repo is safe to make public later.
Add a server compose (full stack, Postgres on the LAN, scheduler on, host-visible
pgdata bind mount) and a localdev compose (webapp only, no DB, scheduler off) that
points at the central DB. Document the single-shared-database topology, the
exactly-one-scheduler rule, and YOUTUBE_API_KEY for unattended backfill that does
not depend on a 7-day OAuth refresh token.
