remove broken auth UI from header; PR firms now authenticate at distribute platform

- Header.tsx: remove "SIGN IN" and "REGISTER" buttons from the top
  utility bar and the mobile drawer. Auth for PR firms / writers lives
  at distribution.relevantmediaproperties.com now; the local /client-login
  and /register routes are no longer the right entry point.
- src/middleware.ts (new): 301-redirect /wp-login, /wp-login.php,
  /wp-admin, /wp-admin/*, /login, /client-login, and /register to
  https://distribution.relevantmediaproperties.com/login so existing
  bookmarks and old WP-era links land somewhere useful instead of 404.
- Newsletter signup form, social icons, country selector all retained.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/middleware.ts

@@ -0,0 +1,39 @@
+import { NextResponse, type NextRequest } from "next/server";
+
+// PR firms / writers authenticate at the distribute platform, not here.
+// Anything that looks like a WordPress login or the bare /login path
+// redirects there so old bookmarks don't dead-end.
+const AUTH_TARGET = "https://distribution.relevantmediaproperties.com/login";
+
+const REDIRECT_PATHS = new Set<string>([
+  "/login",
+  "/wp-login",
+  "/wp-login.php",
+  "/wp-admin",
+  "/client-login",
+  "/register",
+]);
+
+export function middleware(req: NextRequest) {
+  const path = req.nextUrl.pathname;
+  if (
+    REDIRECT_PATHS.has(path) ||
+    path.startsWith("/wp-admin/") ||
+    path.startsWith("/wp-login/")
+  ) {
+    return NextResponse.redirect(AUTH_TARGET, 301);
+  }
+  return NextResponse.next();
+}
+
+export const config = {
+  matcher: [
+    "/login",
+    "/wp-login",
+    "/wp-login.php",
+    "/wp-admin/:path*",
+    "/wp-login/:path*",
+    "/client-login",
+    "/register",
+  ],
+};