fix: ensure nginx has access to writable temp directories

Dockerfile

@@ -15,6 +15,7 @@ RUN npm run build
 # Stage 2: Build Python backend + serve frontend with Nginx
 FROM python:3.9-slim
 
+# Set working directory
 WORKDIR /app
 
 # Install Python dependencies
@@ -37,11 +38,16 @@ COPY frontend/nginx.conf /etc/nginx/conf.d/default.conf
 RUN rm -rf /usr/share/nginx/html && \
     ln -s /app/frontend_build /usr/share/nginx/html
 
-# Copy script to run both frontend and backend
+# Create writable temp dirs for nginx to avoid permission error
+RUN mkdir -p /app/tmp/body /app/tmp/proxy /app/tmp/fastcgi /app/tmp/uwsgi /app/tmp/scgi && \
+    chmod -R 777 /app/tmp
+
+# Copy start script
 COPY start.sh /start.sh
 RUN chmod +x /start.sh
 
-# Expose Hugging Face compatible port
+# Expose port 7860 for Hugging Face
 EXPOSE 7860
 
+# Start both backend and nginx
 CMD ["/start.sh"]