v4.24.0

• Key shared Lake package artifacts by the exact installed Lean and Lake
  executable digests. Existing /1 package artifacts are source-only donors;
  the first build of each project re-shares artifacts under the /2 key.
• Let an exact registered dependency graph donate source across toolchain
  versions, while stripping its build tree, and refresh existing project
  attachments when their computed workspace identity changes.
• Report obsolete /1 project artifacts in doctor, reclaim them through
  clean, and refuse publishing moving toolchain spellings such as master
  or undated nightly. Publication also fails early when its input is an
  acquired sparse capsule rather than a source build.