AdScaling
How ad creatives scale inside the ad surface — the Kotlin mirror of the iOS runtime's AdScaling.
FIT: aspect-fit — the whole creative is visible; an aspect mismatch with the surface letterboxes against black bars.
FILL: aspect-fill — the creative covers the whole ad surface and the overflow is cropped symmetrically (never stretched). This is an explicit opt-in for creatives that should cover the ad surface. The web renderer's primary ad creatives use
object-fit: contain; only companion/backdrop artwork usesobject-fit: cover.