fix(api): add rate limiting, file size validation, and timeout handling

- Add Content-Length header check for early file size validation on audio upload
- Add rate limiting (60 req/min) to public watch endpoint
- Add 10-second timeout with AbortController for YouTube and Vimeo oEmbed requests
- Add automatic rate limit cleanup interval for self-hosted servers
- Fix null check for comment.replies in video page content
- Add checkWorkspaceAccess helper for workspace authorization

lib/video-providers/vimeo.ts

@@ -65,9 +65,14 @@ export const vimeoProvider: VideoProvider = {
     const cached = getCachedMetadata(cacheKey);
     if (cached) return cached;
     try {
+      const controller = new AbortController();
+      const timeoutId = setTimeout(() => controller.abort(), 10000); // 10 second timeout
+
       const response = await fetch(
-        `https://vimeo.com/api/oembed.json?url=https://vimeo.com/${videoId}`
+        `https://vimeo.com/api/oembed.json?url=https://vimeo.com/${videoId}`,
+        { signal: controller.signal }
       );
+      clearTimeout(timeoutId);
       
       if (!response.ok) {
         throw new Error('Failed to fetch video metadata');