Improve MineGeo UI and application flows

lib/multiplayer-api.ts

@@ -81,6 +81,17 @@ export async function multiplayerApi(
     return respond({ id });
   }
   const id = z.string().uuid().parse(path[1]);
+  const linked = await client
+    .from("multiplayer_rooms")
+    .select("tournament_id")
+    .eq("id", id)
+    .maybeSingle();
+  if (linked.error) required(linked);
+  if (linked.data?.tournament_id)
+    throw new ServiceError(
+      "Use the tournament page to join or play this event",
+      409,
+    );
   const action = path[2] ?? "view";
   if (action === "discord" && path.length === 3 && request.method === "POST") {
     const view = required(