Reported as the library "breaking" on iOS whenever a title showed a banner
instead of a cover: the tile expanded out of its bounds.
`PosterImage` already meant to prevent exactly this — its own comment said a
banner "would otherwise report a much wider intrinsic size than the card and
overflow into neighboring cards" — and the guard it used, a flexible frame plus
`.clipped()`, does not do it. `scaledToFill` answers a proposal with a size
that COVERS it, i.e. larger; `.frame(maxWidth: .infinity, maxHeight: .infinity)`
then clamps that answer to infinity, which is no clamp at all, so the image's
size propagates straight up through `aspectRatio(2/3, .fit)` and decides the
tile.
Measured offscreen with ImageRenderer, one LazyVGrid column at 170pt:
460x215 header, before poster 1750.9 x 818.4 tile 545.6 x 255.0
460x215 header, after poster 170.0 x 255.0 tile 170.0 x 255.0
300x450 cover, either poster 170.0 x 255.0 tile 170.0 x 255.0
A 545pt tile in a 170pt column is what the report is describing, and the cover
case coming out right either way is why this only ever showed on the titles
whose cover was missing.
The fix gives the sizing role to something that has no opinion about it:
`Color.clear` takes the proposal, and the art rides as its overlay, where it
can be drawn but never measured. `LibraryCoverflowView` reuses `PosterImage`
directly, so it is fixed by the same change.
enricobuehler
59fc9294ea