Refactor golden image handling in backup upload process</message>

<message>Update the _set_golden_from_path function to improve the handling of existing golden image files. Replace the existing unlink logic with a more robust method that safely removes files or broken symlinks using the missing_ok parameter. This change enhances the reliability of the backup upload process by ensuring that stale references are properly cleared before setting a new golden image path.

backup-from-device/gnss-guard/tm-gnss-guard/server/Dockerfile

@@ -0,0 +1,40 @@
+# GNSS Guard Server - Dockerfile
+FROM python:3.11-slim
+
+# Set environment variables
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+
+# Set working directory
+WORKDIR /app
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc \
+    libpq-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy requirements first (for better caching)
+COPY requirements.txt .
+
+# Install Python dependencies
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy application code
+COPY . .
+
+# Create non-root user for security
+RUN useradd --create-home --shell /bin/bash appuser && \
+    chown -R appuser:appuser /app
+USER appuser
+
+# Expose port
+EXPOSE 8000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD python -c "import requests; requests.get('http://localhost:8000/auth/check', timeout=5)" || exit 1
+
+# Run uvicorn
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]
+