Nonspecific rmtree failure when accidentally resuming a job twice

If you try to quickrun resume the same transformation twice, you can end up in a situation where two parallel attempts at completing the job are happening.

When that happens, one of the jobs can eventually fail with this kind of stack trace:

Traceback (most recent call last):
  File "/home/ialibay/software/mambaforge/install/envs/openfe/bin/openfe", line 6, in <module>
    sys.exit(main())
             ~~~~^^
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/site-packages/click/core.py", line 1485, in __call__
    return self.main(*args, **kwargs)
           ~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/site-packages/click/core.py", line 1406, in main
    rv = self.invoke(ctx)
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/site-packages/click/core.py", line 1873, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/site-packages/click/core.py", line 1269, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/site-packages/click/core.py", line 824, in invoke
    return callback(*args, **kwargs)
  File "/home/ialibay/github/openfe/src/openfecli/utils.py", line 116, in wrapper
    result = function(*args, **kwargs)
  File "/home/ialibay/github/openfe/src/openfecli/commands/quickrun.py", line 160, in quickrun
    dagresult = execute_DAG(
        dag,
    ...<5 lines>...
        n_retries=2,
    )
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/site-packages/gufe/protocols/protocoldag.py", line 526, in execute_DAG
    shutil.rmtree(scratch)
    ~~~~~~~~~~~~~^^^^^^^^^
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/shutil.py", line 763, in rmtree
    _rmtree_safe_fd(stack, onexc)
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/shutil.py", line 704, in _rmtree_safe_fd
    onexc(func, path, err)
    ~~~~~^^^^^^^^^^^^^^^^^
  File "/home/ialibay/software/mambaforge/install/envs/openfe/lib/python3.13/shutil.py", line 665, in _rmtree_safe_fd
    orig_st = os.lstat(name, dir_fd=dirfd)
FileNotFoundError: [Errno 2] No such file or directory: PosixPath('results/test/scratch_HybridTopologyMultiStateSimulationUnit-d254ea3d8d0a495bb69ed7c57c219520_attempt_0')

This is probably because the other runner has already deleted the scratch repository. It may make sense to capture that error and provide users with a clearer error.

Start at src/openfecli/commands/quickrun.py around line 160, then follow the execute_DAG call shown in the traceback into gufe's protocoldag.py. Reproduce a duplicated quickrun resume if possible and inspect how scratch cleanup reaches shutil.rmtree. Done means the duplicate-resume failure reports a clearer user-facing error instead of the nonspecific FileNotFoundError.