Expose branchFileChanges (updatedPackageFiles + updatedArtifacts) in the Renovate Report

[zeitlinger]

Proposal

Add a report field that emits, per Renovate branch, the manifest writes and lockfile/artifact writes Renovate computed for that branch — path + content, keyed by branchName. Roughly:

{
  "branchFileChanges": [
    {
      "branchName": "renovate/lodash-4.x",
      "updatedPackageFiles": [{ "path": "package.json", "contents": "..." }],
      "updatedArtifacts":    [{ "path": "package-lock.json", "contents": "..." }]
    }
  ]
}

Off by default. Enable via --report-include-file-changes=true on the CLI (or the equivalent config field).

Why

Downstream tooling that inspects Renovate PRs wants to verify that a PR's actual head contents match what Renovate would have written. Without the report surface, the only current option is to run Renovate a second time against the PR base and diff — which is fragile, expensive, and produces false positives when transitive registry state drifts between the first and second run.

Emitting what Renovate already computed removes both problems.

Prior work

I've prototyped this as a patch on zeitlinger/renovate:minos-dump — commit 11d93c01f. Happy to open a PR if there's interest.

Question

• Is this a report surface you'd consider adding? Any concerns about payload size, opt-in gating, or naming?
• Related: any reason --dry-run=full (which today runs lockfile updaters) shouldn't be the mode this pairs with?