(cherry picked from commit 096d1f22fd50e2728e9ba7df3d5be83b3b55c45f)

... instead of an external script. update_desktop_database requires
meson 0.59.0, so bump the version requirement.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/241>

Ignored in Meson < 0.60.0, deprecated since 0.60.1 and fatal since 0.61.0.

data/appdata/meson.build:2:0: ERROR: Function does not take positional arguments.
data/meson.build:5:0: ERROR: Function does not take positional arguments.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/242>

Update mozjs, gjs and eslint before starting to use new language
features.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/243>

This is needed for eslint to accept class fields.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/243>

As a side-effect of supporting class fields, regular constructors
now work in GObject subclasses. Using _init() still works and
there's no functional difference, but it's simply much nicer
to use the same syntax for all classes.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/243>

We'll replace them with a script that runs during CI.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/245>

This was done to have a single list of source files for the
resource and js78 tests. Now that the tests have been removed,
there is no longer a reason for keeping the list in meson.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/245>

The template will already call `dnf clean all` after processing
packages and the script, so no need for us to call it as well.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/245>

Pull in gjs-ci-tools, which includes a script to perform a simple
syntax check similar to `js91 --compile-only`, then run the script
during CI to replace the previously removed compile-time tests.

The script uses gjs instead of the SpiderMonkey shell, which means
it will always use the same engine version with the same feature set
as gjs.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/245>

Property bindings need to access the value before instance fields
are added. Address this by handling the case where the backing
property is undefined, and simply return the empty string.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/244>

For subclasses, instance fields are added right after super() returns.
That is too late for GObject properties that are passed to the
constructor, as the "initialization" overrides the previously set
value.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/244>

Class fields look more standardized than an object literal passed
to a wrapper function, and are hopefully closer to what a future
decorator syntax will look like.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/246>

The list of users in a room can be fairly large, so popping up
a quick in-app notification with long columns of names for a
couple of seconds isn't great.

The existing user-list popover already provides a cleaner,
searchable UI for the same data, so leverage that instead
of the notification.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/247>

Instead of driving the parser from the entry, pass the entry at
construction time and handle events internally. This is similar
to what we do with tab completion, and likewise will allows us
to attach a popover to the entry.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/247>

The current "command queue" UI is clumsy. A popover seems a better
choice, as it is still more lightweight than a dialog, but also
separated from the chat area.

It is also more flexible, in case we want to improve the layout
with something like title/subtitle later, but for now keep the
existing labels to not introduce string changes late in the cycle.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/247>

This is the last user of the command queue. Replace it, so that
we can remove the queue and all related code.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/247>

It is no longer used.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/247>

It was only used by the command output queue.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/247>

Commit 33368eba moved the initialization of properties that back
GObject properties into fields, because in subclasses `this` only
becomes available after chaining up with `super()`.

However fields don't work in that case, because they are applied
right before the `super()` call returns, which means they override
the values that were passed to the GObject constructor.

In cases where we don't need any special handling in getters or
setters, we can remove the backing variable altogether and rely
on automatic accessors.

In other cases we can add the CONSTRUCT flag to force the setter
to run with the default value.

In either case, we can get rid of the fields.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/248>

Commit 56efe1af fixed the issue of accidentally overriding
the construct-time value, but now the setters try to access template
children that are only initialized after the GObject constructor.

So solve this differently by replacing the "special" bits from the
setters with a property binding and notify handler. Besides fixing
the warning, this also allows us to rely on gjs' auto accessors.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/249>

The top-level path is searched as a fallback, but only after trying
fallback names. Using a proper theme path ensures that custom icons
take priority, and features like recoloring works.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

This takes care of initializing libadwaita, loading its stylesheet
and support the system's dark-style preference.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

Now that we switched to AdwApplication, we can automate loading
the custom stylesheet by simply using the expected name and
resource prefix.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

The old names have been deprecated, switch to the replacements that
are now part of the libadwaita API.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

Adwaita no longer uses the accent color for the selection background,
and therefore uses the regular color for text. We should do the same,
so just drop the special case.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

The * selector propagates the override to the entire hierarchy below
the row, which in GTK4 includes the context popover.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

The difference between menu- and custom popovers doesn't matter
in the default GTK4 style, but it does for the new Adwaita theme.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

libadwaita defines a set of style classes as part of its API, including
a set of typography styles for labels. Use those instead of pango markup
for better platform consistency.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

libadwaita defines a set of style classes as part of its API, including
a set of typography styles for labels. Use those instead of pango markup
for better platform consistency.

As a bonus, we can drop the custom setters as we no longer add markup
to the title, so we can simply bind the property.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

libadwaita provides a standard widget for status pages and placeholders.
Use it for less code and more consistency :-)

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

The initial setup window is another component where the standard
StatusPage widget can replace quite a bit of custom UI.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

To fit the current design patterns[0], add an icon to the text label,
so that it gets the same flat styling as all the other headerbar
elements.

[0] https://blogs.gnome.org/alexm/2021/09/10/cleaning-up-header-bars/

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

The current design trend is to use row-based preferences, and libadwaita
provides dedicated widgets to implement those in a standard manner.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

libadwaita includes support for in-app notifications. It is action-based
like GNotifications, so in preparation to adopting it, delegate the undo
action to an action.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

We finally have a standard widget for in-app notifications, so use
those instead of our own (much less polished) implementation.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

It's not an app notification, and it's only used by subclasses
in the RoomStack module.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

They are unused after switching to AdwToast, cheers.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

We are using the split headerbar pattern, which becomes a lot more
convenient with libadwaita's headerbar subclass.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

Instead of splitting both titlebar and content area, and synchronizing
the split widths, move the headerbars into the content area and split
that, with a separator in between.

Not only is this simpler because it matches the visual layout, it is
also easier to make adaptive later.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

While we're still quite far from being truly usable on mobile, we
can at least adapt the main layout:
 - use a leaflet as top-level container
 - navigate between sidebar/chat area as necessary
 - show all titlebar decorations when folded

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/250>

Reflect the ui/style changes from the libadwaita port.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/251>

Update NEWS.

Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/251>