With the previous preparations in place, it is time to take the plunge.
As both the app and the portal use the same small library for handling
external windows, port everything at once to avoid the hassle of building
and installing two versions of the library.
With the portal using GTK4 now, all extensions must port their preference
widgets as well.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1495>
Currently there is no indication that an extension had an error except
for the sensitivity of the switch (which may have a different cause).
This is useful information to users, so add a small error indicator
alongside the updates icon and show the actual error in the details.
https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2337
Currently the switches handle position reflects the requested
extension state (as in: the user (de)activated the switch),
while the actual extension state is reflected by the underlying
state.
That doesn't work well when the switch is insensitive though (for
example on error), because the desaturation neuters the color
that reflects the state.
Address this by resetting the switch handle to the state when
making it insensitive.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1263
The Extensions app code is now independent enough from the rest of the code
base to move it to its own subprojects, like we did for the extensions-tool.
This allows for stand-alone builds of the app, which we are about to use
for distributing it as flatpak.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1133
