Fix nginx temp directory permissions in Dockerfile

- Create nginx temp directories during build
- Set proper ownership (www-data) and permissions (775)
- Fixes 'Permission denied' error on PDF uploads

Dockerfile

@@ -55,9 +55,16 @@ RUN composer dump-autoload --optimize
 # Create log directory for supervisor
 RUN mkdir -p /var/log/supervisor
 
+# Create nginx temp directories and set permissions
+RUN mkdir -p /var/lib/nginx/tmp/client_body \
+    /var/lib/nginx/tmp/proxy \
+    /var/lib/nginx/tmp/fastcgi \
+    /var/lib/nginx/tmp/uwsgi \
+    /var/lib/nginx/tmp/scgi
+
 # Set permissions
-RUN chown -R www-data:www-data /var/www/html/storage /var/www/html/bootstrap/cache
+RUN chown -R www-data:www-data /var/www/html/storage /var/www/html/bootstrap/cache /var/lib/nginx/tmp
-RUN chmod -R 775 /var/www/html/storage /var/www/html/bootstrap/cache
+RUN chmod -R 775 /var/www/html/storage /var/www/html/bootstrap/cache /var/lib/nginx/tmp
 
 # Copy nginx configuration
 COPY docker/nginx.conf /etc/nginx/nginx.conf