Netlify Adds Deploy Previews for Stacked PRs

What shipped? Netlify now generates a Deploy Preview for every pull request in a GitHub stacked PR workflow, not just the first PR in the chain.

What changed? Previously, only the first pull request in a GitHub stack got a Deploy Preview. Additional PRs in the stack — each representing a layer of a larger change — had no preview at all. Now every eligible PR in the stack gets its own preview automatically, with no additional configuration. Works with GitHub's existing stacked PR tooling.

Why a builder cares: Stacked PRs are the standard pattern for splitting large feature work into reviewable chunks. Missing previews on intermediate PRs defeated the purpose — you couldn't visually validate each layer independently. This closes that gap. If you ship with stacked PRs and Netlify, this is immediate quality-of-life improvement.