FR: Add cache for generated audio
It seems that Read Aloud generates the audio each time it's opened (and makes the request).
I'm using it for language practive hance repeating a couple of times of generated sentence. Currently each time I try to play the audio there is a noticeable delay (suggesting each time new request is being made) which on the one hand is slighly inconvenient and on the other - increase the token usage of selected services.
This one could be nice! I'm using the API keys and prevent a repeated request for an audio played a few seconds ago would be also useful use case, not only the delay.
We should cache generated audio in the engine implementations in tts-engines.js. This would be a good enhancement