Changes to make `ep split-commits` work (#46160)

1. `apply_diff` will create a file if the diff says so (by starting with
`--- /dev/null`)
2. Update examples format to match recent changes
3. `ep split-commits` can work with a stream of inputs and generate `n`
samples per input
4. Unicode handling fixes

Release Notes:

- N/A
92b0f144c0Oleksiy Syvokon committed on 1/6/2026, 2:38:44 PM· committed by GitHubparent8829f1d
4 files changedLine totals unavailable