Sound through the DVI cable: picodvi.AudioOut

[mikeysklar]

RP2350 boards can send sound with the DVI picture, so a TV or monitor with speakers plays it. Proposal:

audio = picodvi.AudioOut(fb)  # fb is a picodvi.Framebuffer
audio.play(sample, loop=False)

Same methods and properties as audiobusio.I2SOut.

Question	Proposed answer
New class or Framebuffer method?	New class, so any audiocore sample just works
Sample rates	48 kHz only. Other rates raise ValueError
Which modes	640-wide only; the 720 mode's sync is too short
Cost when unused	None on the cable, about 6 KB flash, flag to turn it off
Cost when used	About 120-150 KB internal RAM, about 19% CPU while playing

Working branch, tested on Fruit Jam: https://github.com/mikeysklar/circuitpython/tree/picodvi-audioout

Is this shape OK?

Initial work by Phillip Torrone. Claude Code helped write this.

[mikeysklar]

Discussion moved to #11510.