feat(upload): enhance audio upload handling and user feedback

- Introduced a new warning for users uploading non-FLAC or WAV formats, indicating that these formats should only be used as a last resort.
- Added functionality to highlight files needing format attention in the upload queue.
- Updated the UI to provide clearer guidance on acceptable audio formats during uploads.
- Improved documentation to reflect changes in upload requirements and user interface updates.

services/api/internal/platform/sign/sign.go

@@ -1,5 +1,5 @@
 // Package sign — HMAC-подписи ссылок, которые клиент открывает без заголовка Authorization
-// (обложки в <img>, стрим в <audio>; docs/decisions.md, ADR-006).
+// (обложки в <img>, стрим в <audio>).
 package sign
 
 import (