Create man pages for tar-diff and tar-patch

Create manual pages for the CLI tools to be included in the RPM package.

## Tasks

- Create `docs/man/tar-diff.1` man page
- Create `docs/man/tar-patch.1` man page
- Add `make man` target to generate/install man pages
- Document all CLI options and usage examples

## Acceptance Criteria

- Man pages render correctly with `man tar-diff` and `man tar-patch`
- Man pages included in `make install`