add version to api, add hello world route to api and optimize the backend's dockerfile

Dockerfile

@@ -1,23 +1,44 @@
+FROM ghcr.io/astral-sh/uv:debian-slim AS builder
+WORKDIR /app
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends ca-certificates gcc python3-dev && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+COPY pyproject.toml uv.lock ./
+
+RUN uv sync --locked
+
 FROM ghcr.io/astral-sh/uv:debian-slim
 ARG VERSION
 LABEL version=${VERSION}
 LABEL description="Docker image for the backend of MediaManager"
 
-ENV IMAGE_DIRECTORY=/data/images
-ENV TV_SHOW_DIRECTORY=/data/tv
-ENV MOVIE_DIRECTORY=/data/movies
-ENV TORRENT_DIRECTORY=/data/torrents
-ENV OPENID_ENABLED=FALSE
+ENV IMAGE_DIRECTORY=/data/images \
+    TV_SHOW_DIRECTORY=/data/tv \
+    MOVIE_DIRECTORY=/data/movies \
+    TORRENT_DIRECTORY=/data/torrents \
+    OPENID_ENABLED=FALSE \
+    PUBLIC_VERSION=${VERSION}
 
-RUN apt update && apt install -y ca-certificates gcc python3-dev
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends ca-certificates && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app
+
+COPY --from=builder /usr/local/lib/python3.*/site-packages /usr/local/lib/python3.*/site-packages/
+
 COPY --chmod=755 mediamanager-backend-startup.sh .
 COPY media_manager ./media_manager
 COPY alembic ./alembic
 COPY alembic.ini .
-COPY pyproject.toml .
-COPY uv.lock .
-RUN uv sync --locked
+
+RUN useradd -m appuser && \
+    chown -R appuser:appuser /app /data
+
+USER appuser
 EXPOSE 8000
 CMD ["/app/mediamanager-backend-startup.sh"]