fix(cli): preserve directory basename when uploading to sandbox (#885)

[mjamiv]

Fixes #885.

Summary

openshell sandbox upload <local-dir> <remote-dir> previously flattened the local directory's contents into the remote destination, dropping the source directory's basename. This diverged from the standard scp -r / cp -r semantics that operators expect from any *nix-style transfer tool, and could silently shadow files at the destination.

After this change, an upload of foo to /sandbox/dest/ lands at /sandbox/dest/foo/, matching scp -r foo remote:/sandbox/dest/ and cp -r foo /sandbox/dest/. Paths without a meaningful basename (., /) preserve the legacy flat extraction so that idiomatic upload . calls still work as before.

Per #885 maintainer guidance, this is the variant A approach — match scp -r semantics by default — rather than adding an opt-in --preserve-dir flag.

Scope

Single-file change to crates/openshell-cli/src/ssh.rs:

• ssh_tar_upload now uses the computed tar_name for the directory case instead of hardcoded ".".
• New directory_upload_prefix(local_path) helper returns the directory's basename for any path with a meaningful basename, and "." for . / /.
• sandbox_sync_up calls the helper for directory uploads.

Tests

Two new unit tests in the existing tests module:

• directory_upload_prefix_uses_basename_for_named_directories — covers /tmp/upload-test, foo, and ./parent/nested.
• directory_upload_prefix_falls_back_to_dot_for_basename_less_paths — covers . and /.

Reproduction (matches #885)

Before:

```
$ mkdir -p /tmp/upload-test/sub
$ echo a > /tmp/upload-test/a.txt
$ echo b > /tmp/upload-test/sub/b.txt
$ openshell sandbox upload /tmp/upload-test /sandbox/dest/
$ ssh 'ls /sandbox/dest/'
a.txt sub/ # upload-test/ basename dropped
```

After:

```
$ openshell sandbox upload /tmp/upload-test /sandbox/dest/
$ ssh 'ls /sandbox/dest/'
upload-test/ # basename preserved
$ ssh 'ls /sandbox/dest/upload-test/'
a.txt sub/
```

Compatibility note

This is a breaking change in the directory-upload behavior. Callers that relied on the flatten-into-destination semantics for directories (other than . / /) will need to either:

• adjust their destination path (/sandbox/dest/foo/ → /sandbox/dest/), or
• pass . from inside the source directory to preserve the legacy behavior.

Single-file uploads are unaffected.

Worth a release-note line. Happy to add a BREAKING CHANGE footer to the commit message or a docs(changelog): follow-up if that fits the project's release process.

[copy-pr-bot]

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