feat: update game image proxy settings for immediate cache revalidation

Author: David-H-Afonso

nginx.conf

@@ -43,7 +43,8 @@ server {
 
     # Proxy game images to API server
     # API_IMAGES_URL will be replaced at runtime via entrypoint
-    location /game-images/ {
+    # ^~ prevents the static-assets regex below from intercepting .jpg/.png URLs
+    location ^~ /game-images/ {
         set $api_images_url "API_IMAGES_URL_PLACEHOLDER";
         proxy_pass $api_images_url;
         proxy_set_header Host $host;
@@ -56,10 +57,11 @@ server {
         proxy_hide_header Cache-Control;
         proxy_hide_header Pragma;
         proxy_hide_header Expires;
-        # 1-day cache so replaced images (same filename) are refreshed the next day.
-        # The API sends ETags – nginx passes them through for conditional GET (304).
-        expires 1d;
-        add_header Cache-Control "public, max-age=86400, must-revalidate";
+        # no-cache: browser must revalidate every request using the ETag.
+        # If the image hasn't changed the API returns 304 (no body transferred).
+        # This means a replaced image (same filename) is visible immediately.
+        expires -1;
+        add_header Cache-Control "no-cache, must-revalidate";
     }
 
     # Cache static assets