Improve Dockerfile build times

Dockerfile

@@ -1,22 +1,33 @@
 FROM node:22-bookworm-slim
 
 RUN apt-get update && \
-    apt-get install -y build-essential python3 python3-pip && \
+    apt-get install -y \
+        build-essential \
+        python3 \
+        python3-pip && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
 USER node
 ENV HOME=/home/node \
-	PATH=/home/node/.local/bin:$PATH
-    
-COPY --chown=node . $HOME/app
+    PATH=/home/node/.local/bin:$PATH
+
+# Copy only the requirements.txt first to leverage Docker cache
+COPY --chown=node requirements.txt $HOME/app/
 WORKDIR $HOME/app
-COPY --chown=node requirements.txt .
-RUN pip install --no-cache-dir --break-system-packages -U pip && \
-    pip install --no-cache-dir --break-system-packages -r requirements.txt
+
+# Install Python dependencies
+RUN pip install --no-cache-dir \
+        --break-system-packages \
+        -U pip && \
+    pip install --no-cache-dir \
+        --break-system-packages \
+        -r requirements.txt
 
 COPY --chown=node hardhat hardhat
 WORKDIR $HOME/app/hardhat
+
+# Install Node.js dependencies and compile
 RUN npm install && \
     npx hardhat compile && \
     rm -rf contracts test cache
@@ -24,6 +35,6 @@ RUN npm install && \
 WORKDIR $HOME/app
 COPY --chown=node api .
 COPY --chown=node init_tasks.py ./
-ENV HF_DATASET=braindao/solbench-humaneval-for-solidity-v2
+ENV HF_DATASET='braindao/solbench-humaneval-for-solidity-v2'
 
 ENTRYPOINT ["./scripts/start-api.sh"]