feat(web): WebAuthn relying-party helper (host-derived rpID/origin)

web/lib/auth-rp.ts

@@ -0,0 +1,21 @@
+import "server-only";
+import { headers } from "next/headers";
+
+export type RpInfo = {
+  rpID: string;
+  origin: string;
+  rpName: string;
+};
+
+export async function getRpInfo(): Promise<RpInfo> {
+  const hdrs = await headers();
+  const host = hdrs.get("x-forwarded-host") ?? hdrs.get("host") ?? "localhost:8010";
+  const rpID = host.split(":")[0];
+  const proto = hdrs.get("x-forwarded-proto") ?? "http";
+  const origin = `${proto}://${host}`;
+  return {
+    rpID,
+    origin,
+    rpName: "CM Bot V2",
+  };
+}