Derive API path from frontend config URL

Dockerfile

@@ -17,6 +17,7 @@ COPY upstream/HubFrontend/ ./
 COPY docker/hcaptcha-sitekey.patch /tmp/hcaptcha-sitekey.patch
 COPY docker/remove-analytics.mjs /tmp/remove-analytics.mjs
 COPY docker/replace-fallback-avatar.mjs /tmp/replace-fallback-avatar.mjs
+COPY docker/use-config-url-api-path.mjs /tmp/use-config-url-api-path.mjs
 
 RUN if grep -q 'sitekey="1788882d-3695-4807-abac-7d7166ec6325"' src/routes/auth/login.js; then \
         patch -p1 < /tmp/hcaptcha-sitekey.patch; \
@@ -29,6 +30,7 @@ RUN if grep -q 'sitekey="1788882d-3695-4807-abac-7d7166ec6325"' src/routes/auth/
 
 RUN node /tmp/remove-analytics.mjs
 RUN node /tmp/replace-fallback-avatar.mjs
+RUN node /tmp/use-config-url-api-path.mjs
 
 ARG ASSETS_BASE=""
 ARG VITE_USE_MULTIHUB=false
@@ -45,6 +47,13 @@ ENV ASSETS_BASE=${ASSETS_BASE} \
 RUN test -n "$VITE_HCAPTCHA_SITEKEY" \
     || (echo "VITE_HCAPTCHA_SITEKEY must be set." >&2; exit 1)
 
+RUN if [ "$VITE_USE_MULTIHUB" != "true" ]; then \
+        case "$VITE_CONFIG_URL" in \
+            */client/config/global|*/client/config/global/) ;; \
+            *) echo "VITE_CONFIG_URL must end with /client/config/global." >&2; exit 1 ;; \
+        esac; \
+    fi
+
 RUN npm run build
 
 # Electron entry points are not part of the web deployment.