API Diff Validation

Confirm that the public APIs claimed by an API diff actually shipped in the target build, and that each new API traces to a real PR. This is the verification layer on top of the pure api-diff skill (which only produces the diff reports).

Use it to catch, before release notes are written:

• APIs present in the diff but missing from the shipped build (a missed revert, a rename, or an API kept internal),
• new APIs with no implementing PR (suspicious / mis-attributed).

Inputs

• A generated API diff for the milestone (the api-diff/ reports), or the target release identity.
• build-metadata.json — nuget.source (the dnceng dotnet<major> feed) and the ref-pack package versions for the exact build.
• The milestone's changes.json / candidate PRs (for cross-referencing).