Layers on ramekin-agent with Rust nightly (edition 2024 requires it),
llvm-tools-preview, grcov, and bc for coverage reporting.

Assisted-by: Claude Opus 4.6 via pi

diff --git a/.ramekin/Dockerfile b/.ramekin/Dockerfile
new file mode 100644
index 0000000..0ea130b
--- /dev/null
+++ b/.ramekin/Dockerfile
@@ -0,0 +1,19 @@
+FROM ramekin-agent
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    bc \
+    && rm -rf /var/lib/apt/lists/*
+
+# Rust nightly (edition 2024)
+ENV RUSTUP_HOME=/usr/local/rustup \
+    CARGO_HOME=/usr/local/cargo \
+    PATH="/usr/local/cargo/bin:$PATH"
+RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs \
+    | sh -s -- -y --default-toolchain nightly --profile minimal \
+    && rustup component add llvm-tools-preview \
+    && cargo install grcov
+
+
+WORKDIR /workspace
+
+ENTRYPOINT ["pi"]