Why: U4 acceptance needs a reproducible real-browser run: build the
RDM binary from its origin/main, seed projects/ingest via the command
API, serve with auth on, and drive Playwright against vite preview.
Evidence: scripts/e2e.sh --seed-only smoke (in progress this task);
frontend pin points at the Playwright harness commit.
Impact: dev tooling only (.tmp artifacts ignored; no runtime changes).
Refs: task feature/rdm-e2e-acceptance; frontend feature branch of
the same name.
