add toast with regards to bluetooth headphones

I think we should be able to detect if we are connected to bluetooth headphones (by the playback time starting to advance normally, then waiting to catch up to the audio and then continuing to advance).
In these cases we should display a warning or an explanation that nudges the user to use wired headphones instead.

No file, test, or entry point is named in the issue. Start by tracing playback-time handling and the existing toast or notification mechanism, then verify the proposed lag signal with Bluetooth and wired headphones. Done means the app reliably identifies the described condition and shows a clear recommendation to use wired headphones.

Written by the indexing model from the issue text.