ci(release): record every release as an empty commit on main

[pranav-new-relic]

Summary

Extend the tag-triggered release workflow (`release.yml`) so that every published release also lands as a marker commit on `main`.

• New job `commit-release-notes` runs after `build` (which creates the GitHub Release), so we can consume the release's canonical URL.
• Subject: `chore(release): Open Install Library Release vX.Y.Z, D Month YYYY`
• Body: the per-commit change list (`git log ..` in `- subject (short-sha)` form) plus a `Release: <html_url>` deep-link to the GitHub release page.
• Empty commit — no changelog file is added (repo has none); `git log main` becomes the release history.
• Uses `github-actions[bot]` via `${{ secrets.GITHUB_TOKEN }}`, matching existing automation identity.
• One rebase-retry to survive a concurrent push to main.

Test plan

• Push a throwaway pre-release tag (e.g. `v0.83.0-rc1`) after this merges and verify the new job runs, the `Commit message preview` step prints the expected format, and the empty commit appears on main.
• If branch protection blocks the push, add `github-actions[bot]` to the "Allow specified actors to bypass required pull requests" list on the main branch protection rule (or swap `GITHUB_TOKEN` for a PAT stored as a repo secret).