🌬️ Breathing sound

[Cynnexis]

Is your feature request related to a problem? Please describe.
During the breathing exercise, it would be nice to have a sound cue for inhaling and exhaling.

Describe the solution you'd like
A breathing-in and breathing-out sound can be used at the beginning of each animation.

Describe alternatives you've considered
Other sounds can be used, as long as they are different to tell the breathing-in and breathing-out animations apart.

Additional context
The sound should be copyleft and royalty-free.