Aggiunge il mute del microfono in diretta per evitare claim YouTube sulla musica in palestra.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/config/locales/app.en.yml

@@ -436,6 +436,8 @@ en:
     preview_waiting: Waiting for signal…
     pause: Pause stream
     resume: Resume stream
+    mute: Mute audio
+    unmute: Unmute audio
     stop: End stream
     modal:
       set_won_title: Set won
@@ -471,9 +473,12 @@ en:
       unknown_period: "—"
       resumed: Stream resumed
       paused_cover: "Stream paused — cover on air"
+      muted: "Audio muted — YouTube is not receiving the microphone"
+      unmuted: "Microphone audio restored"
       closed: Stream closed
       resume_error: Error resuming the stream
       pause_error: Error pausing the stream
+      mute_error: Error muting audio
       close_error: Error closing
       close_confirm: Permanently close the live stream?
       link_unavailable: Link not available