Perf: cache Nitro client assets and parallelize client page

- Serve /swf and /nitro-assets (~2.8GB) with 7-day Cache-Control plus
  stale-while-revalidate so client opens stop re-fetching hundreds of
  files while asset updates still propagate in the background
- Issue the SSO ticket and the online count query in parallel on the
  client page to shave a round-trip off the critical render path

next.config.ts

@@ -125,6 +125,28 @@ const nextConfig: NextConfig = {
 					},
 				],
 			},
+			{
+				// Nitro client payload (~2.8GB across swf/nitro-assets): without
+				// caching every client open re-downloads hundreds of files.
+				// Fresh for 7 days, then serve stale + revalidate in background
+				// so asset updates still propagate without blocking players.
+				source: "/swf/(.*)",
+				headers: [
+					{
+						key: "Cache-Control",
+						value: "public, max-age=604800, stale-while-revalidate=2592000",
+					},
+				],
+			},
+			{
+				source: "/nitro-assets/(.*)",
+				headers: [
+					{
+						key: "Cache-Control",
+						value: "public, max-age=604800, stale-while-revalidate=2592000",
+					},
+				],
+			},
 			{
 				source: "/images/(.*)",
 				headers: [{ key: "Cache-Control", value: "public, max-age=86400" }],