Make build package workflow more flexible

[Marc-André Moreau (mamoreau-devolutions)]

Summary

• allow explicit package versions when building from non-release or patch branches
• add github environment selection with auto, test, and prod handling
• upload signed binaries from the package job for easy retrieval from workflow runs

Notes

• keeps branch-based version inference when no explicit version is provided
• package and publish steps continue to consume artifacts from the signed package-job outputs