Bake Nginx config into image at build time instead of bind mount - fixes Coolify deployment

docker/nginx/Dockerfile

@@ -0,0 +1,7 @@
+FROM nginx:alpine
+
+# Copy the Nginx configuration into the image at build time.
+# This avoids bind-mount issues on production servers (e.g., Coolify).
+COPY default.conf /etc/nginx/conf.d/default.conf
+
+EXPOSE 80