Generate changes.json

Produce the authoritative changes.json input for a preview, RC, or GA release milestone.

This is the VMR-aware data acquisition stage of the release notes pipeline:

1. Determine which milestone(s) are active
2. Resolve the correct --base and --head refs
3. Run release-notes generate changes
4. Write changes.json into the correct release-notes/ folder

When to use

• A new preview, RC, or GA milestone needs fresh shipped-change data
• The user wants to know whether multiple preview milestones are active at once
• The release notes branch should be refreshed after the VMR moved forward
• changes.json is missing, stale, or suspected to have the wrong ref selection

Preview-only branch targeting