Fix file upload limit over 2MB in production with HTTPS

- Use printf instead of echo to correctly write php.ini with newlines
  (Alpine ash echo does not interpret \n, leaving the file malformed
  and PHP falling back to its 2MB default)
- Add nginx.conf with client_max_body_size 25M as front-end proxy
- Start nginx on port 8080 via supervisord; move artisan serve to
  internal port 8081 so nginx can proxy requests with proper limits

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nginx.conf

@@ -0,0 +1,28 @@
+worker_processes auto;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    include       /etc/nginx/mime.types;
+    default_type  application/octet-stream;
+    sendfile      on;
+    keepalive_timeout 65;
+
+    client_max_body_size 25M;
+    proxy_read_timeout 120s;
+    proxy_send_timeout 120s;
+
+    server {
+        listen 8080;
+
+        location / {
+            proxy_pass         http://127.0.0.1:8081;
+            proxy_set_header   Host              $host;
+            proxy_set_header   X-Real-IP         $remote_addr;
+            proxy_set_header   X-Forwarded-For   $proxy_add_x_forwarded_for;
+            proxy_set_header   X-Forwarded-Proto $scheme;
+        }
+    }
+}