Add audio parameter to player playlist and auto-mark deployment status

- api.py: include 'audio' (on/off) field in playlist JSON served to players,
  derived from the muted toggle in the manage playlist page
- players.py: include 'audio' field in legacy player playlist builder
- api.py: auto-flip deployment_status pending/deploying -> deployed when a
  player sends feedback (player is confirmed running)
- players_list.html: poll deployment status for pending/failed badges so the
  players list live-updates once a player starts sending feedback
- .dockerignore: exclude runtime data/ volume dir from build context

app/blueprints/players.py

@@ -578,6 +578,7 @@ def get_player_playlist(player_id: int) -> List[dict]:
             'duration': getattr(content, '_playlist_duration', content.duration or 10),
             'position': getattr(content, '_playlist_position', 0),
             'muted': getattr(content, '_playlist_muted', True),
+            'audio': 'off' if getattr(content, '_playlist_muted', True) else 'on',
             'filename': content.filename
         })