v12.0.0-beta.30

Fixed

• Files for an older task opens in a few seconds instead of about 30. One
  renamed file used to make QualityLayer compare the whole tree, and pictures
  and recordings were decrypted only to count zero lines.
• Showing a task's cost no longer reads your whole cost history several times.
  On a long-used computer one task's cost could take more than 500 MB of memory
  for a moment; it now reads only that task's rows.
• Opening a task that you haven't looked at since the App restarted is quick:
  its build fingerprint is kept, and its timeline asks git twice instead of
  twice for every commit.