Exact blueprint versions

You can now pick the version a blueprint release publishes under by setting spec.version in the blueprint YAML, whether that's 1.4.0, 2.0.0-rc.1, or a 1.4.3 maintenance release after 2.0.0 is out. The number your customers and support docs cite is the number Ryvn publishes: syncing the same content twice reuses the existing release, and different content under a version that's already taken fails as a conflict instead of getting renumbered. ryvn plan shows the release it will create before you sync, and leaving spec.version out keeps automatic numbering.