chore: update Dockerfile to use Python 3.12 and improve dependency installation

Dockerfile

@@ -1,16 +1,38 @@
-FROM python:3.9.18-slim
+FROM python:3.12-alpine3.22 AS builder
 
-RUN --mount=type=cache,target=/var/cache/apt \
-    apt-get update && apt-get install -y git git-lfs
+RUN pip install --no-cache-dir --upgrade pip \
+    && pip install --no-cache-dir uv
 
-WORKDIR /usr/src/app
+WORKDIR /app
 
-COPY release-requirements.txt .
-RUN --mount=type=cache,target=/root/.cache/pip \
-    pip install -r release-requirements.txt
+RUN --mount=type=cache,target=/root/.cache/uv \
+    --mount=type=bind,source=requirements.txt,target=requirements.txt \
+    --mount=type=bind,source=release-requirements.txt,target=release-requirements.txt \
+    uv venv \
+    && uv pip install -r release-requirements.txt
 
 COPY . .
-RUN --mount=type=cache,target=/root/.cache/pip \
-    pip install .
 
-ENTRYPOINT [ "github-backup" ]
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv pip install .
+
+
+FROM python:3.12-alpine3.22
+ENV PYTHONUNBUFFERED=1
+
+RUN apk add --no-cache \
+    ca-certificates \
+    git \
+    git-lfs \
+    && addgroup -g 1000 appuser \
+    && adduser -D -u 1000 -G appuser appuser
+
+COPY --from=builder --chown=appuser:appuser /app /app
+
+WORKDIR /app
+
+USER appuser
+
+ENV PATH="/app/.venv/bin:$PATH"
+
+ENTRYPOINT ["github-backup"]