docs: update upload guides with exact file types, limits, and CORS requirements

- Updates `content/docs/guides/upload-content.md` to list supported video formats (`.mp4`, `.webm`, `.mov`, `.mkv`, `.ts`, `.m3u8`, `.mpg`, `.mpeg`) and thumbnail formats.
- Adds a recommended file size limit of 2GB with an explanation (browser memory constraints).
- Clarifies CORS configuration for Cloudflare R2 to explicitly require AWS SDK v3 headers.
- Updates `content/docs/getting-started.md` to distinguish between direct upload formats and external hosting formats.
- Adds metadata validation details (Title required).

Co-authored-by: PR0M3TH3AN <[email protected]>

content/docs/getting-started.md

@@ -22,7 +22,7 @@ Ready to jump in? Here's everything you need to know to start watching and shari
 
 ### Step 2: Prepare Your Video
 
-1. Host your video at an HTTPS URL that browsers can stream directly (MP4/WebM/HLS/DASH all work). You can use your own CDN, Cloudflare Stream, an R2 bucket, or any static site host—as long as the link begins with `https://`.
+1. Host your video at an HTTPS URL that browsers can stream directly. If you are uploading a file directly via bitvid, we accept **MP4, WebM, MOV, MKV, TS, M3U8, MPG, and MPEG**. For external hosting, ensure the format is streamable (MP4/WebM/HLS/DASH). You can use your own CDN, Cloudflare Stream, an R2 bucket, or any static site host—as long as the link begins with `https://`.
 2. (Optional but recommended) Generate a WebTorrent magnet so viewers can fall back to peer-to-peer delivery. Desktop apps like [WebTorrent Desktop](https://webtorrent.io/desktop/) or command-line tools can create the magnet for you.
 3. Double-check that either the hosted URL or the magnet (or both) is ready before you open the Upload modal.