chore: move test-only helpers to test file

integrations/playback/allanime/client.go

@@ -730,17 +730,6 @@ func detectStreamType(sourceURL string) string {
 	return "unknown"
 }
 
-func isLikelyM3U8(data []byte) bool {
-	return bytes.HasPrefix(bytes.TrimSpace(data), []byte("#EXTM3U"))
-}
-
-func isLikelyMP4(data []byte) bool {
-	if len(data) < 8 {
-		return false
-	}
-	return string(data[4:8]) == "ftyp"
-}
-
 func detectEmbedType(rawURL string) string {
 	lower := strings.ToLower(rawURL)
 	embedHosts := []string{"streamwish", "streamsb", "mp4upload", "ok.ru", "gogoplay", "streamlare"}