Fixes#7236
Supersedes #7249
This removes all of our `focusedValue`-based tracking of the surface
title and moves it completely to the window controller. The window
controller now sets up event listeners (via Combine) when the focused
surface changes and updates the window title accordingly.
There is some complicated logic here to handle when we lose focus to
something other than a surface. In this case, we want our title to be
the last focused surface so long as it exists.
First, this commit modifies libghostty to use a single unified action
dispatch system based on a tagged union versus the one-off callback
system that was previously in place. This change simplifies the code on
both the core and consumer sides of the library. Importantly, as we
introduce new actions, we can now maintain ABI compatibility so long as
our union size does not change (something I don't promise yet).
Second, this moves a lot more of the functions call on a surface into
the action system. This affects all apprts and continues the previous
work of introducing a more unified API for optional surface features.
Fixes#734
I don't know much about SwiftUI, but here's why I think this works.
- Moving the `inspectorVisible` logic to an `onChange` ensures the view
has at least seen that change.
- The dispatch to the main thread is still necessary to ensure the view
hierarchy has completely updated after `inspectorVisible`.
Note that this fix is to correctly regain focus. We still lose window
focus very briefly.
