Variable substitution in HostName

### Checklist

- [x] Using latest version on the [App Store](http://itunes.apple.com/app/id1156707581)
- [x] Read the [docs](http://blink.sh/docs/)
- [x] Searched for [existing GitHub issues](https://github.com/blinksh/blink/issues)

### Configuration

Blink 18.5.1.1094
IPadOS 26.4

### Describe the bug

Using .ssh/config like this:

```
Host host1 host2 host3
HostName %h.some.domain
```

It seems like variable substitution doesn’t work in HostName as I’m getting this error:

```
Error connecting to host1. operationError(msg: "Failed to set option \'SSH_OPTIONS_HOST\'")
```

### Expected behavior

The %h in HostName gets substituted with actual hostname given to ssh command.

Could you please look at it? I seems this is already supported for ProxyCommand. Could you please make it work for HostName too? It would save me a lot of trouble generating separate .ssh/config just for Blink.

Thank you for this wonderful tool!

Start by tracing SSH configuration handling for .ssh/config and compare how variable substitution is implemented for ProxyCommand versus HostName. Reproduce the configuration with Host host1 host2 host3 and HostName %h.some.domain; done means the %h value is expanded before the SSH host option is set and the connection succeeds.

Written by the indexing model from the issue text.