feat: add TikTok follower count support to follower metrics and labels

lib/followers/index.ts

@@ -6,6 +6,7 @@ export interface FollowerCounts {
   youtube: number | null;
   roblox: number | null;
   discord: number | null;
+  tiktok: number | null;
 }
 
 export interface FollowerInfo {
@@ -20,13 +21,17 @@ export async function getFollowerCounts(): Promise<FollowerCounts> {
     getDiscordMemberCount(),
   ]);
 
-  return { youtube, roblox, discord };
+  const tiktokEnv = process.env.TIKTOK_FOLLOWERS;
+  const tiktok = tiktokEnv ? Number(tiktokEnv) : null;
+
+  return { youtube, roblox, discord, tiktok };
 }
 
 const followerLabels: Record<keyof FollowerCounts, string> = {
   youtube: "ผู้ติดตาม",
   roblox: "ผู้ติดตาม",
   discord: "สมาชิก",
+  tiktok: "ผู้ติดตาม",
 };
 
 export function getCountForLink(name: string, counts: FollowerCounts): FollowerInfo | null {