directory <two-random-words> is not empty and cannot be removed in method keybase.1.createPersonalRepo

All keybase git operations fail with some variant of above.

Also included: Error 218.

6.2.4-20240101011938+ae7e4a1c15

Start by reproducing the failure in keybase.1.createPersonalRepo using the reported Keybase version, and inspect the directory-not-empty message and Error 218 across the affected Git operations. Done means the relevant Git operations no longer fail because the directory cannot be removed, with the reported error condition covered by a regression test.

Written by the indexing model from the issue text.