Make sure all tools wait for keypress on exit when in DOS 2.x

Care needs to be taken to make sure, especially for the query tools (FLD, FLH, FCONFIG), that a message similar to
```
PRESS [RETURN] TO CONTINUE
```

Is displayed if not running in a CLI dos. You can see examples of this in various tools, e.g.:
https://github.com/FujiNetWIFI/fujinet-config-tools/blob/master/flh/src/main.c#L90

Care should be taken to display this when an SIO query fails, so that the error message can be seen.

Start by inspecting the entry points for FLD, FLH, FCONFIG, and the other tools, then compare their exit handling with flh/src/main.c around the referenced example. Verify behavior in DOS 2.x outside a CLI, including failed SIO queries; done means the relevant tools display the return prompt so messages remain visible.

Written by the indexing model from the issue text.