Start Sentio SDK 4.0 development on main. With this release(major) commit,
main's next semantic-release run cuts 4.0.0-rc.1 (per the release/major rule).

The v3 line is preserved on develop/v3 (forked at the v3.8.0 release commit
092e7d65) and publishes prereleases on the rc3 channel. This also adds
develop/v3 to the release topology so it stays consistent across branches:

- Add { name: 'develop/v3', prerelease: 'rc3' } to the SDK, CLI, and action
  release configs
- Trigger the publish workflow on develop/v3 and publish it to the rc3 npm
  dist-tag; parse the full branch name so develop/v3 maps correctly
- Gate the RC GitHub-release cleanup on stable (no "-") versions so -rc3
  publishes don't delete every pre-release GitHub release

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>