[Draft] Forward client audio

[Cabbache]

This is a WIP based on the poc by @yume-chan to add the feature requested in #3880

[Hideman85]

Looking forward to this feature, would be really good in phone call experience while working for instance.

[Cabbache]

It is working and somewhat stable on high latency. Tested from a laptop running linux and an android 16 device.

The new arguments are like this:

<     --client-audio-source=source
<         Inject audio into the device microphone from a device or file.
<         The source can be:
<           - A device name (e.g., "Microphone", "default")
<           - A file path prefixed with "file://" (e.g.,
<         "file:///path/to/audio.mp3")
<         Supported file formats: MP3, OGG, WAV, FLAC, etc.
< 

<     --list-audio-sources
<         List available audio input sources on the client computer.

This is not enabled by default so you have to explicitly add the argument, e.g scrcpy --client-audio-source default