feat(media-kit): refresh audience insights and sponsor links

lib/youtube-channel-stats.ts

@@ -0,0 +1,65 @@
+export type YouTubeChannelStats = {
+  subscribers: number | null;
+  views: number;
+  videos: number;
+};
+
+type YouTubeChannelsResponse = {
+  items?: Array<{
+    statistics?: {
+      hiddenSubscriberCount?: boolean;
+      subscriberCount?: string;
+      viewCount?: string;
+      videoCount?: string;
+    };
+  }>;
+};
+
+function parseCount(value: string | undefined) {
+  if (!value) return null;
+  const parsed = Number.parseInt(value, 10);
+  return Number.isFinite(parsed) ? parsed : null;
+}
+
+export async function getYouTubeChannelStats(): Promise<YouTubeChannelStats | null> {
+  const apiKey = process.env.YOUTUBE_API_KEY?.trim();
+  if (!apiKey) return null;
+
+  const params = new URLSearchParams({
+    part: "statistics",
+    key: apiKey,
+  });
+  const channelId = process.env.YOUTUBE_CHANNEL_ID?.trim();
+
+  if (channelId) {
+    params.set("id", channelId);
+  } else {
+    params.set("forHandle", "@poyrazavsever");
+  }
+
+  try {
+    const response = await fetch(
+      `https://www.googleapis.com/youtube/v3/channels?${params.toString()}`,
+      { next: { revalidate: 3600 } },
+    );
+
+    if (!response.ok) return null;
+
+    const data = (await response.json()) as YouTubeChannelsResponse;
+    const statistics = data.items?.[0]?.statistics;
+    const views = parseCount(statistics?.viewCount);
+    const videos = parseCount(statistics?.videoCount);
+
+    if (!statistics || views === null || videos === null) return null;
+
+    return {
+      subscribers: statistics.hiddenSubscriberCount
+        ? null
+        : parseCount(statistics.subscriberCount),
+      views,
+      videos,
+    };
+  } catch {
+    return null;
+  }
+}