cp -r fails to create directories

Attempting to copy a tree of files using cp -r fails when the first file of a subdirectory doesn't exist in the target:

```
🐚 cp -r out out2
Traceback (most recent call last):
File "", line 198, in _run_module_as_main
File "", line 88, in _run_code
File "C:\Users\coombsjason\.local\bin\cp.exe\__main__.py", line 7, in
File "C:\Users\coombsjason\pipx\venvs\cmdix\Lib\site-packages\cmdix\__init__.py", line 127, in run
return run_subcommand(commandname, argv)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\coombsjason\pipx\venvs\cmdix\Lib\site-packages\cmdix\__init__.py", line 165, in run_subcommand
args.func(args)
File "C:\Users\coombsjason\pipx\venvs\cmdix\Lib\site-packages\cmdix\command\cp.py", line 58, in func
args.handle(_copy, args, dest, src)
File "C:\Users\coombsjason\pipx\venvs\cmdix\Lib\site-packages\cmdix\command\cp.py", line 66, in handle_recursive
walk(_copy, args, dest, src)
File "C:\Users\coombsjason\pipx\venvs\cmdix\Lib\site-packages\cmdix\command\cp.py", line 104, in walk
_copy(srcfile, dstfile)
File "C:\Python312\Lib\shutil.py", line 435, in copy
copyfile(src, dst, follow_symlinks=follow_symlinks)
File "C:\Python312\Lib\shutil.py", line 262, in copyfile
with open(dst, 'wb') as fdst:
^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '\\build\\Microsoft.NETFramework.ReferenceAssemblies.net45.targets'
```

Start with cmdix/command/cp.py, especially handle_recursive, walk, and the _copy call shown in the traceback. Reproduce `cp -r out out2` with a subdirectory whose first file is absent from the destination, then verify that recursive copying creates the needed directories and completes without FileNotFoundError.

Written by the indexing model from the issue text.