Make hCaptcha site key configurable

Dockerfile

@@ -6,20 +6,39 @@ WORKDIR /build
 
 ENV ELECTRON_SKIP_BINARY_DOWNLOAD=1
 
+RUN apt-get update \
+    && apt-get install --yes --no-install-recommends patch \
+    && rm -rf /var/lib/apt/lists/*
+
 COPY upstream/HubFrontend/package.json upstream/HubFrontend/package-lock.json upstream/HubFrontend/.npmrc ./
 RUN --mount=type=cache,target=/root/.npm npm ci
 
 COPY upstream/HubFrontend/ ./
+COPY docker/hcaptcha-sitekey.patch /tmp/hcaptcha-sitekey.patch
+
+RUN if grep -q 'sitekey="1788882d-3695-4807-abac-7d7166ec6325"' src/routes/auth/login.js; then \
+        patch -p1 < /tmp/hcaptcha-sitekey.patch; \
+    elif grep -q 'VITE_HCAPTCHA_SITEKEY' src/routes/auth/login.js; then \
+        echo "Upstream already supports VITE_HCAPTCHA_SITEKEY; skip the deployment patch."; \
+    else \
+        echo "Unsupported upstream hCaptcha configuration." >&2; \
+        exit 1; \
+    fi
 
 ARG ASSETS_BASE=""
 ARG VITE_USE_MULTIHUB=false
 ARG VITE_MULTIHUB_DISCOVERY=""
 ARG VITE_CONFIG_URL
+ARG VITE_HCAPTCHA_SITEKEY
 
 ENV ASSETS_BASE=${ASSETS_BASE} \
     VITE_USE_MULTIHUB=${VITE_USE_MULTIHUB} \
     VITE_MULTIHUB_DISCOVERY=${VITE_MULTIHUB_DISCOVERY} \
-    VITE_CONFIG_URL=${VITE_CONFIG_URL}
+    VITE_CONFIG_URL=${VITE_CONFIG_URL} \
+    VITE_HCAPTCHA_SITEKEY=${VITE_HCAPTCHA_SITEKEY}
+
+RUN test -n "$VITE_HCAPTCHA_SITEKEY" \
+    || (echo "VITE_HCAPTCHA_SITEKEY must be set." >&2; exit 1)
 
 RUN npm run build