refactor: Update player seek functionality to use consistent position field across schemas and services

app/api/v1/player.py

@@ -137,10 +137,10 @@ async def seek(
     """Seek to specific position in current track."""
     try:
         player = get_player_service()
-        await player.seek(request.position_ms)
-        return MessageResponse(message=f"Seeked to position {request.position_ms}ms")
+        await player.seek(request.position)
+        return MessageResponse(message=f"Seeked to position {request.position}ms")
     except Exception as e:
-        logger.exception("Error seeking to position %s", request.position_ms)
+        logger.exception("Error seeking to position %s", request.position)
         raise HTTPException(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail="Failed to seek",