fix docker

backend/Dockerfile

@@ -18,19 +18,21 @@ RUN apt-get update && apt-get install -y \
 # Install UV for faster Python package management
 RUN pip install uv
 
-# Copy pyproject.toml and uv.lock
-COPY pyproject.toml uv.lock ./
+# Create non-root user early
+RUN useradd --create-home --shell /bin/bash app && \
+    chown -R app:app /app
 
-# Install Python dependencies
+# Switch to app user
+USER app
+
+# Copy pyproject.toml and uv.lock
+COPY --chown=app:app pyproject.toml uv.lock ./
+
+# Install Python dependencies as app user
 RUN uv sync --frozen --no-dev
 
 # Copy application code
-COPY . .
-
-# Create non-root user
-RUN useradd --create-home --shell /bin/bash app && \
-    chown -R app:app /app
-USER app
+COPY --chown=app:app . .
 
 # Expose port
 EXPOSE 8000