Add no index edge

Signed-off-by: Christopher Hakkaart <christopher.hakkaart@gmail.com>

Author: christopher-hakkaart

docs/netlify/edge-functions/robots-tag.js

@@ -0,0 +1,23 @@
+// Adds `X-Robots-Tag: noindex` for direct hits to docs-migration.netlify.app,
+// while leaving responses unchanged when the request is proxied through
+// docs.seqera.io (so the canonical URL is the only one indexed).
+//
+// Detection relies on the upstream proxy forwarding the original hostname in
+// `X-Forwarded-Host`, which nginx, Cloudflare and most CDNs do by default.
+
+export default async (request, context) => {
+  const response = await context.next();
+
+  const forwardedHost = request.headers.get("x-forwarded-host") || "";
+  const isProxiedFromSeqera = forwardedHost.toLowerCase().includes("seqera.io");
+
+  if (!isProxiedFromSeqera) {
+    response.headers.set("X-Robots-Tag", "noindex");
+  }
+
+  return response;
+};
+
+export const config = {
+  path: "/*",
+};