Fix windows download path issues

[jnoller]

This fixes the following crash below when doing sisyphus download using a windows host. This is mostly pathing fixes with some defensive code for the windows logic to confirm the tar command worked.

Confirmed on Linux and Windows hosts using OSX as the client.

(sisyphus)  ✘   ~/Code/sisyphus   main±  sisyphus download -H 34.239.150.243 -P llama.cpp -d builds
INFO Connected (version 2.0, client OpenSSH_for_Windows_8.0)
INFO Authentication (publickey) failed.
INFO Connected (version 2.0, client OpenSSH_for_Windows_8.0)
INFO Authentication (publickey) successful!
INFO '34.239.150.243' is a Windows host
INFO Build complete
INFO gguf-0.15.4575-py310haa95532_0.tar.bz2 already transmuted
INFO gguf-0.15.4575-py311haa95532_0.tar.bz2 already transmuted
INFO gguf-0.15.4575-py312haa95532_0.tar.bz2 already transmuted
INFO gguf-0.15.4575-py39haa95532_0.tar.bz2 already transmuted
INFO llama.cpp-0.0.4575-cpu_v1_mkl_h4262f35_0.tar.bz2 already transmuted
INFO llama.cpp-0.0.4575-cpu_v2_mkl_h0bdc4df_40.tar.bz2 already transmuted
INFO llama.cpp-0.0.4575-cpu_v3_mkl_h393b973_50.tar.bz2 already transmuted
INFO llama.cpp-0.0.4575-cuda124_v1_h6cbc5b3_200.tar.bz2 already transmuted
INFO llama.cpp-0.0.4575-cuda124_v2_h16922bf_240.tar.bz2 already transmuted
INFO llama.cpp-0.0.4575-cuda124_v3_hf3fb316_250.tar.bz2 already transmuted
INFO llama.cpp-tools-0.0.4575-py310haa95532_0.tar.bz2 already transmuted
INFO llama.cpp-tools-0.0.4575-py311haa95532_0.tar.bz2 already transmuted
INFO llama.cpp-tools-0.0.4575-py312haa95532_0.tar.bz2 already transmuted
INFO llama.cpp-tools-0.0.4575-py39haa95532_0.tar.bz2 already transmuted
INFO Downloading package tarballs in '\sisyphus\llama.cpp\build\win-64'
INFO [chan 21] Opened sftp connection (server version 3)
Traceback (most recent call last):
  File "/opt/homebrew/anaconda3/envs/sisyphus/bin/sisyphus", line 8, in <module>
    sys.exit(cli())
             ~~~^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/click/core.py", line 1161, in __call__
    return self.main(*args, **kwargs)
           ~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/click/core.py", line 1082, in main
    rv = self.invoke(ctx)
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/click/core.py", line 1697, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/click/core.py", line 1443, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/click/core.py", line 788, in invoke
    return __callback(*args, **kwargs)
  File "/Users/jesse/Code/sisyphus/sisyphus/main.py", line 171, in download
    h.download(package, destination, all)
    ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/jesse/Code/sisyphus/sisyphus/host.py", line 448, in download
    self.connection.get(tf.replace("\\", "/"))
    ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/fabric/connection.py", line 897, in get
    return Transfer(self).get(*args, **kwargs)
           ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/fabric/transfer.py", line 170, in get
    self.sftp.get(remotepath=remote, localpath=local)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/paramiko/sftp_client.py", line 840, in get
    size = self.getfo(
        remotepath,
    ...<3 lines>...
        max_concurrent_prefetch_requests,
    )
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/paramiko/sftp_client.py", line 795, in getfo
    file_size = self.stat(remotepath).st_size
                ~~~~~~~~~^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/paramiko/sftp_client.py", line 493, in stat
    t, msg = self._request(CMD_STAT, path)
             ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/paramiko/sftp_client.py", line 857, in _request
    return self._read_response(num)
           ~~~~~~~~~~~~~~~~~~~^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/paramiko/sftp_client.py", line 909, in _read_response
    self._convert_status(msg)
    ~~~~~~~~~~~~~~~~~~~~^^^^^
  File "/opt/homebrew/anaconda3/envs/sisyphus/lib/python3.13/site-packages/paramiko/sftp_client.py", line 942, in _convert_status
    raise IOError(text)
OSError: Failure

[DenisDupeyron]

I clearly remember testing this in both situations and it worked, so I wonder what's going on here.

I'll look at it again because that's weird.