Refactor Dockerfile to enhance user creation and cache directory handling

Dockerfile

@@ -15,7 +15,15 @@ FROM python:${PYTHON_VERSION}-slim as base
 # the application crashes without emitting any logs due to buffering.
 ENV PYTHONUNBUFFERED=1
 
-RUN adduser appuser
+ARG UID=10001
+RUN adduser \
+    --disabled-password \
+    --gecos "" \
+    --home "/nonexistent" \
+    --shell "/sbin/nologin" \
+    --no-create-home \
+    --uid "${UID}" \
+    appuser
 
 USER appuser
 
@@ -27,8 +35,8 @@ ENV TRANSFORMERS_CACHE=$HOME/app/.cache/huggingface/hub
 WORKDIR $HOME/app
 
 COPY --chown=appuser ./requirements.txt requirements.txt
-RUN mkdir -p /app/.cache \
-    && chown -R appuser:appuser /app/.cache
+RUN mkdir -p $HOME/app/.cache \
+    && chown -R appuser:appuser $HOME/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.