BREAKING CHANGE: SFTP/SCP now respects the agent's configured directory.
If your workspace agent has a custom `dir` configured in Terraform, SFTP
and SCP connections will now land there instead of `$HOME`. Previously,
only SSH and rsync respected this setting, which caused confusing behavior
where `scp file.txt coder:.` and `rsync file.txt coder:.` would put files
in different places. If you have scripts that relied on SFTP/SCP always
using `$HOME` regardless of agent configuration, you may need to use
explicit paths instead.