Updated dockerfile / ci setup

Dockerfile

@@ -1,30 +1,36 @@
-FROM haskell:9.10
+FROM haskell:9.10.2-bullseye AS builder
 
-# Install system dependencies
-RUN apt-get update && apt-get install -y \
-    git \
-    curl \
-    && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y curl git && rm -rf /var/lib/apt/lists/*
 
-# Install Node.js (for GitHub Actions compatibility)
 RUN curl -fsSL https://deb.nodesource.com/setup_22.x | bash - && \
     apt-get install -y nodejs && \
     rm -rf /var/lib/apt/lists/*
 
-# Update cabal and install Haskell tools
 RUN cabal update && \
     cabal install --install-method=copy --installdir=/usr/local/bin \
-    fourmolu \
-    hlint \
-    cabal-gild
+    fourmolu hlint cabal-gild
 
-# Verify installations
-RUN ghc --version && \
-    cabal --version && \
-    node --version && \
-    fourmolu --version && \
-    hlint --version && \
-    cabal-gild --version
-
-# Set working directory
 WORKDIR /workspace
+
+FROM haskell:9.10.2-bullseye
+
+RUN apt-get update && apt-get install -y \
+    libgmp10 \
+    curl \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN curl -fsSL https://deb.nodesource.com/setup_22.x | bash - && \
+    apt-get install -y nodejs && \
+    rm -rf /var/lib/apt/lists/*
+
+RUN cabal update
+
+COPY --from=builder /usr/local/bin/cabal /usr/local/bin/
+COPY --from=builder /usr/local/bin/fourmolu /usr/local/bin/
+COPY --from=builder /usr/local/bin/hlint /usr/local/bin/
+COPY --from=builder /usr/local/bin/cabal-gild /usr/local/bin/
+
+WORKDIR /workspace
+
+CMD [ "bash" ]
+