[GuillaumeRx]

Explanation

Adds planChangesetsRelease, which turns the edited release spec into a release plan. Nothing calls it yet.

• Only the packages in the spec are released. The tool filters the changesets to those packages and computes the plan again.
• Spec values override the plan. A raised bump also releases the package's dependents.
• Errors are reported together, in the legacy format.
• The result lists the selected changesets and the applied overrides.

No user-facing change, so no changelog entry.

References

• Depends on feat(create-release-branch): load the Changesets plan and generate the release spec #136

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them