Fixes#5256
This updates the macOS apprt to implement the `OPEN_URL` apprt action to
use the NSWorkspace APIs instead of the `open` command line utility.
As part of this, we removed the `ghostty_config_open` libghostty API and
instead introduced a new `ghostty_config_open_path` API that returns the
path to open, and then we use the `NSWorkspace` APIs to open it (same
function as the `OPEN_URL` action).
This makes it so `zig build run` can take arguments such as
`--config-default-files=false` or any other configuration. Previously,
it only accepted commands such as `+version`.
Incidentally, this also makes it so that the app in general can now take
configuration arguments via the CLI if it is launched as a new instance
via `open`. For example:
open -n Ghostty.app --args --config-default-files=false
This previously didn't work. This is kind of cool.
To make this work, the libghostty C API was modified so that
initialization requires the CLI args, and there is a new C API to try to
execute an action if it was set.
