Add Dockerfile for step 1 host-mediated dispatch

Minimal image: debian bookworm, git, quire user, bare test repo
at /var/quire/repos/foo.git. Entrypoint passes through to docker
exec invocations. No sshd, no quire binary yet.

Assisted-by: GLM-5.1 via pi

diff --git a/Dockerfile b/Dockerfile
new file mode 100644 (file)
index 0000000..18c6bbe
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,32 @@
+FROM debian:bookworm-slim
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+        git \
+        ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN groupadd --system quire \
+    && useradd --system --gid quire --create-home quire
+
+# Volume layout per PLAN.md.
+RUN mkdir -p /var/quire/repos /var/quire/runs \
+    && chown -R quire:quire /var/quire
+
+# Pre-create a test repo for step 1 verification.
+RUN git init --bare /var/quire/repos/foo.git \
+    && chown -R quire:quire /var/quire/repos/foo.git
+
+COPY <<'EOF' /usr/local/bin/entrypoint
+#!/usr/bin/env bash
+set -euo pipefail
+
+exec "$@"
+EOF
+RUN chmod +x /usr/local/bin/entrypoint
+
+USER quire
+WORKDIR /var/quire
+
+ENTRYPOINT ["/usr/local/bin/entrypoint"]
+CMD ["sleep", "infinity"]