Add multi-image compositions, docker setup, tests, and docs

- Add CompositionImage model with multi-image upload and main image flag
- Add composition endpoints: add-images, set-main-image, delete image, by-created-at filter
- Make contact-us by_category public
- Add 24 API tests covering all endpoints
- Add Dockerfile, docker-compose, entrypoint and docker docs
- Add Persian API docs and update README and Postman collection

Co-authored-by: Cursor <cursoragent@cursor.com>

Dockerfile

@@ -0,0 +1,78 @@
+# Multi-stage Dockerfile for Django application
+# Stage 1: Builder stage - Install dependencies
+FROM python:3.11-slim as builder
+
+# Set environment variables
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1 \
+    PIP_NO_CACHE_DIR=1 \
+    PIP_DISABLE_PIP_VERSION_CHECK=1
+
+# Install system dependencies required for building Python packages
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc \
+    postgresql-client \
+    libpq-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+# Create and set working directory
+WORKDIR /app
+
+# Copy requirements file
+COPY requirements.txt .
+
+# Install Python dependencies
+RUN pip install --upgrade pip && \
+    pip install --user -r requirements.txt
+
+# Stage 2: Production stage - Minimal runtime image
+FROM python:3.11-slim
+
+# Set environment variables
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1 \
+    PATH="/home/django/.local/bin:$PATH"
+
+# Install runtime dependencies only
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    postgresql-client \
+    libpq5 \
+    bash \
+    && rm -rf /var/lib/apt/lists/*
+
+# Create non-root user for security
+RUN groupadd -r django && useradd -r -g django django
+
+# Create necessary directories
+RUN mkdir -p /app/staticfiles /app/media && \
+    chown -R django:django /app
+
+# Set working directory
+WORKDIR /app
+
+# Copy Python dependencies from builder stage
+COPY --from=builder /root/.local /home/django/.local
+
+# Copy project files
+COPY --chown=django:django . .
+
+# Copy and set permissions for entrypoint script
+COPY --chown=django:django entrypoint.sh /app/entrypoint.sh
+RUN chmod +x /app/entrypoint.sh
+
+# Switch to non-root user
+USER django
+
+# Expose port
+EXPOSE 8000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
+    CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/api/')" || exit 1
+
+# Use entrypoint script
+ENTRYPOINT ["/app/entrypoint.sh"]
+
+# Default command (can be overridden in docker-compose)
+CMD ["gunicorn", "zonco_backend.wsgi:application", "--bind", "0.0.0.0:8000", "--workers", "3", "--timeout", "120"]
+