Add dynamic footer badge marquee with admin management.

Store badges in Postgres, expose public/admin APIs, render an infinite footer slider, and ship /admin for paste-embed CRUD.

lib/admin-auth.ts

@@ -0,0 +1,15 @@
+import { NextRequest, NextResponse } from "next/server";
+
+export function requireAdmin(req: NextRequest): NextResponse | null {
+  const adminKey = process.env.ADMIN_API_KEY;
+  if (!adminKey) {
+    return NextResponse.json({ error: "Admin API not configured" }, { status: 503 });
+  }
+
+  const auth = req.headers.get("authorization");
+  if (auth !== `Bearer ${adminKey}`) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+
+  return null;
+}