Phase 0: scaffold three-service backend (api/worker/frontend)

api/ (ElysiaJS+Bun WS gateway skeleton), worker/ (Rust, Redis dirty-chunk
stream consumer behind a swappable RenderBackend trait), frontend/
(ElysiaJS+Pug+Tailwind4+Alpine, one server-rendered page) — all three
verified running locally. docker-compose wires them up with postgres,
redis, minio (rendered tile/mesh object storage), and Caddy as reverse
proxy.

worker/Dockerfile

@@ -0,0 +1,9 @@
+FROM rust:1.80 AS build
+WORKDIR /app
+COPY . .
+RUN cargo build --release
+
+FROM debian:bookworm-slim
+RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates && rm -rf /var/lib/apt/lists/*
+COPY --from=build /app/target/release/mcmapper-worker /usr/local/bin/mcmapper-worker
+CMD ["mcmapper-worker"]