add attribution for self host instance

Dockerfile

@@ -48,6 +48,16 @@ RUN npm install --omit=dev --no-audit --no-fund \
 COPY docker/patch-drm-check.js /tmp/patch-drm-check.js
 RUN node /tmp/patch-drm-check.js /app/node/server.js
 
+# Local patch: self-host attribution (docker/patch-attribution.js).
+# The license requires a crawlable link back to https://adventure.land, and
+# the original project should not appear to support this instance. The phrase
+# ships as docker/attribution/{en.js,de.json}; other languages fall back to
+# English. Kept after the npm install so dependency layers stay cached.
+COPY --chown=node:node docker/attribution/en.js /app/languages/en/attribution.js
+COPY --chown=node:node docker/attribution/de.json /app/languages/de/attribution.json
+COPY docker/patch-attribution.js /tmp/patch-attribution.js
+RUN node /tmp/patch-attribution.js /app/htmls/contents/account_help.html
+
 
 FROM ${NODE_IMAGE} AS runtime