Implement two-level workspace isolation pattern for enterprise-scale CI:
- Atomic O(1) workspace restore via filesystem move (no tar/download/extract)
- Separate Library caching for independent restore
- .git preservation for delta operations
- Stale workspace cleanup with configurable retention policies
- 5 new action inputs: childWorkspacesEnabled, childWorkspaceName,
childWorkspaceCacheRoot, childWorkspacePreserveGit,
childWorkspaceSeparateLibrary
- 28 unit tests covering all service methods
This enables enterprise CI where workspaces are 50GB+ and traditional
caching via actions/cache is impractical. On NTFS, workspace restore
is O(1) via atomic rename when source and destination are on the same volume.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
frostebite