Make avatar imager resilient with upstream fallback everywhere

README.md

@@ -682,7 +682,11 @@ The container runs `restart: unless-stopped` and ships a healthcheck that probes
 curl -o avatar.png 'http://127.0.0.1:8082/avatarimage?figure=hr-893-45.hd-600-1.ch-255-66.lg-280-110.sh-295-62&img_format=png&size=l'
 ```
 
-A production issue that this section documents: **the `avatar-imaging-pixinode` image can be removed by a `docker image prune`**, which takes the whole site's avatars offline (502 on `/imaging/*`). Keep the image tagged and re-build it via the commands above if it ever disappears (`docker compose build && docker compose up -d`).
+A production issue that this section documents: **the `avatar-imaging-pixinode` image can be removed by a `docker image prune`**, which used to take the whole site's avatars offline (502 on `/imaging/*`). Keep the image tagged and re-build it via the commands above if it ever disappears (`docker compose build && docker compose up -d`).
+
+### Automatic upstream fallback
+
+Since then the CMS-side avatar proxies (`/api/imaging/avatar` and `/imaging`) are resilient: when the configured upstream (the Polaris container on `8082`) fails or times out, the request is retried against Habbo's public renderer (`https://www.habbo.com/habbo-imaging/avatarimage`), with the `effect` parameter stripped and `img_format` forced to `png`, since the public renderer supports neither. The response is then marked with `X-Imager-Source: primary|fallback` and a shorter `Cache-Control` TTL when served from fallback, so the configured imager is retried soon instead of being masked for hours. No fallback is attempted when the configured upstream already is the Habbo public renderer. As a last line of defence every avatar `<img>` on the site falls back to a grayscale silhouette placeholder instead of a broken-image glyph.
 
 ### Figure string validation (`src/app/api/imaging/avatar/route.ts`)