fix(storage): add panic recovery for malformed MP4 files

- Add defer/recover in getMP4Meta to catch panics from gomedia library
- Implement fallback to ffprobe when MP4 parsing fails
- Fixes "no vosdata" panic when processing certain MP4 files

Also add CLAUDE.md to provide architecture guidance for AI coding assistants.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

storage/telegram/telegram.go

@@ -181,6 +181,11 @@ func (t *Telegram) Save(ctx context.Context, r io.Reader, storagePath string) er
 		switch mtypeStr {
 		case "video/mp4":
 			info, err := getMP4Meta(rs)
+			if err != nil {
+				// Fallback to ffprobe if gomedia fails (e.g., malformed MP4)
+				rs.Seek(0, io.SeekStart)
+				info, err = getVideoMetadata(rs)
+			}
 			if err == nil {
 				media = doc.Video().
 					Duration(time.Duration(info.Duration)*time.Second).