Implement Release Finalization and Post-Release Workflows (C3-C4)

[hdamker]

Problem description

After a release branch is prepared and reviewed (C3), several manual steps remain: finalizing metadata, creating tags, publishing GitHub releases, and syncing artifacts back to main. These operations need automation.

Part of #191 (Develop automation support in support of release management). See PR #338 for the full implementation plan.

Proposed solution

Implement C3-C4 workflows (Steps 3-5 of the release workflow):

1. Release Finalization (after Release Preparation PR merge)

   • Populate final metadata (release_date, src_commit_sha)
   • Create "release commit": chore: finalize release metadata for rX.Y
   • Create git tag (rX.Y) pointing to release commit

2. GitHub Release Publication

   • Publish GitHub Release with:
     • Bundled OpenAPI specifications (all $ref resolved)
     • release-metadata.yaml
     • Generated documentation

3. Post-Release Sync to Main

   • Create PR to main with CHANGELOG entry and README updates
   • Version fields remain placeholders (info.version: "wip")
   • For public releases: Lock PRs targeting just-released versions

4. Reference Tags

   • Create src/X.Y tag on main at branch point
   • Marks commit for potential maintenance branch creation

5. Release Progress Tracker Updates

   • Real-time status triggered by workflow completion
   • Integration with project-administration#38

Dependencies

• Requires Phase 4 release branch automation complete

Success criteria

• End-to-end release finalization tested
• Post-release sync PRs created automatically
• Release Progress Tracker integration functional

Milestone

Target completion: April 30, 2026 (Fall26 M1)