add unknown server and unknown player and impl player embed

src/app/server/[platform]/[hostname]/page.tsx

@@ -1,3 +1,4 @@
+import { embedFallback } from "@/common/embed-fallback";
 import { capitalizeFirstLetter } from "@/common/string-utils";
 import { LookupServer } from "@/components/lookup-server";
 import { NotFound } from "@/components/not-found";
@@ -18,15 +19,15 @@ type Params = {
 export async function generateMetadata({ params: { platform, hostname } }: Params): Promise<Metadata> {
   const server = await getData(platform, hostname);
   if (!server) {
-    return {
-      title: "Unknown Server",
-    };
+    return embedFallback({ title: "Unknown Server", description: "Server not found" });
   }
 
   const { hostname: serverHostname, players } = server;
-  let favicon = null;
+
+  let favicon = null; // Server favicon
 
   if (platform === ServerPlatform.Java) {
+    // Java specific
     const javaServer = server as JavaMinecraftServer;
     favicon = javaServer.favicon && javaServer.favicon.url;
   }