[MattiasBuelens]

Summary

Each slide in the TV demo's home carousel now shows a hero image behind the stream's title, instead of a plain colored gradient.

• Stream gains @DrawableRes image: Int. The images are in app/src/main/res/drawable-nodpi/stream_*.jpg, at most 1920 px wide.
• StreamSlide draws the image with ContentScale.Crop, then a SlideScrim (a dark gradient from the left and from the bottom) so the white text stays readable.
• Image sources:
  • Bip Bop: public domain.
  • Elephant's Dream: CC BY 2.5.
  • Sintel: CC BY 3.0.
  • Livesim and Test card: frames of the DASH-IF Livesim test stream, captured in the demo app. The Test card image adds a "CC" badge.
• A new short app/README.md describes the demo app and credits the images.
• The home screen screenshot in the Android TV getting started guide is re-rendered with Robolectric to show the new carousel. It is now docs/assets/tv-demo-home.jpg (a JPEG, because the photos make a PNG much larger).

Link to Devin session: https://dolby.devinenterprise.com/sessions/c92e3de4d3b0416384ebe04af7ef9499
Open in Devin Desktop: https://dolby.devinenterprise.com/desktop/session/c92e3de4d3b0416384ebe04af7ef9499?variant=devin
Requested by: @MattiasBuelens

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring