Refactor Dockerfile to improve cache directory handling and user permissions

Dockerfile

@@ -21,7 +21,6 @@ RUN adduser \
     --gecos "" \
     --home "/nonexistent" \
     --shell "/sbin/nologin" \
-    --no-create-home \
     --uid "${UID}" \
     appuser
 
@@ -35,15 +34,15 @@ ENV TRANSFORMERS_CACHE=$HOME/app/.cache/huggingface/hub
 WORKDIR $HOME/app
 
 COPY --chown=appuser ./requirements.txt requirements.txt
-RUN mkdir -p $HOME/app/.cache \
-    && chown -R appuser:appuser $HOME/app/.cache
+RUN mkdir -p /app/.cache \
+    && chown -R appuser:appuser /app/.cache
 
 # Download dependencies as a separate step to take advantage of Docker's caching.
 # Leverage a cache mount to /root/.cache/pip to speed up subsequent builds.
 # Leverage a bind mount to requirements.txt to avoid having to copy them into
 # into this layer.
 RUN python -m pip install --upgrade pip \
-    && python -m pip install --no-cache-dir -r requirements.txt
+    && pip install -r requirements.txt
 
 # Copy the source code into the container.
 COPY --chown=appuser . $HOME/app