ep: Add option to split datasets by project (#55071)

`ep split --stratify=project` will use the first component of
`cursor_path`, which is a worktree name. This is an alternative to
`--stratify=repo` in absence of `repository_url`


Release Notes:

- N/A
095b57bb26Oleksiy Syvokon committed on 4/28/2026, 12:33:48 PM· committed by GitHubparente712f3c
1 file changedLine totals unavailable