build: optimize Docker image and switch to production server

- Add --no-install-recommends flag to apt-get to reduce image size
- Add ca-certificates package for secure HTTPS connections
- Clean pip cache after installing dependencies (rm -rf /root/.cache/pip)
- Replace Flask development server with Gunicorn for production deployment
- Configure Gunicorn with 4 workers, 120s timeout, and access/error logging
- Binding to 0.0.0.0:5001 for container networking

Dockerfile

@@ -1,7 +1,7 @@
 FROM python:3.11-slim
 
 # Install system dependencies for Pillow and Tesseract
-RUN apt-get update && apt-get install -y \
+RUN apt-get update && apt-get install -y --no-install-recommends \
     tesseract-ocr \
     libtesseract-dev \
     libfreetype6-dev \
@@ -18,7 +18,7 @@ RUN apt-get update && apt-get install -y \
     wget \
     unzip \
     git \
-    && fc-cache -f -v \
+    ca-certificates \
     && rm -rf /var/lib/apt/lists/*
 
 # Download and install select Google Fonts from GitHub
@@ -60,8 +60,9 @@ WORKDIR /app
 # Copy requirements first for better caching
 COPY requirements.txt .
 
-# Install Python dependencies
-RUN pip install --no-cache-dir -r requirements.txt
+# Install Python dependencies and clear cache
+RUN pip install --no-cache-dir -r requirements.txt && \
+    rm -rf /root/.cache/pip
 
 # Copy application files
 COPY app.py .
@@ -76,5 +77,5 @@ EXPOSE 5001
 # Set environment variables
 ENV PYTHONUNBUFFERED=1
 
-# Run the application
-CMD ["python", "app.py"]
+# Run the application with Gunicorn
+CMD ["gunicorn", "--bind", "0.0.0.0:5001", "--workers", "4", "--timeout", "120", "--access-logfile", "-", "--error-logfile", "-", "app:app"]