chore(config): centralize feature settings

lib/leaderboard/discord.ts

@@ -1,4 +1,5 @@
 import "server-only";
+import { getDiscordServerConfig } from "@/lib/config/server";
 
 export type DiscordVoiceChannel = {
   id: string;
@@ -52,11 +53,7 @@ export async function getCurrentDiscordVoiceChannels() {
     return channelCache.data;
   }
 
-  const token = process.env.DISCORD_BOT_TOKEN;
-  const guildId = process.env.DISCORD_GUILD_ID;
-  if (!token || !guildId) {
-    throw new Error("Discord channel access is not configured.");
-  }
+  const { token, guildId } = getDiscordServerConfig();
 
   const response = await fetch(
     `https://discord.com/api/v10/guilds/${guildId}/channels`,