Build installable packages in CI, and replace COSMIC rather than sit beside it

Bumps both forks to the commits that install at upstream's paths, and adds
the packaging that follows from it.

packaging/ holds one definition per distribution -- an RPM spec, a PKGBUILD
and a Debian control template -- and each wraps a tree that `just install`
has already staged rather than compiling again inside the packaging tool.
Building 27 Rust components a second time to produce bytes that already
exist costs hours and creates a way for the packaged desktop and the built
one to drift apart.

One package per distribution, not one per component. Fedora splits COSMIC
into 27 packages, which is right for a distribution tracking upstream. This
is a fork that replaces the desktop as a unit: there is no supported
combination in which you take the HyprCosmic cosmic-comp and the
distribution's cosmic-session, and one package says so accurately.

All three declare a conflict with the distribution's cosmic-comp and
cosmic-session, and stop rather than resolve it. Obsoletes would let a
routine install quietly remove the desktop the machine is currently
running; removing COSMIC stays a decision a person makes.

.github/workflows/packages.yml builds all three, each inside a container of
the distribution it targets, because nothing here is statically linked and
a package built elsewhere records sonames the installing machine will not
have. It runs on tags and on demand rather than on every push -- three full
desktop builds is hours of runner time for artifacts nobody downloads --
and a tag opens a draft release, not a published one.

The RPM file list is generated from the staged tree, and claims a directory
only when no package already owns it. A naive list would have the package
own /usr, /usr/bin and /usr/share, which belong to `filesystem`.

README follows the same reframe: the install goes to /usr/bin, the package
route is documented first, and the conflict is explained where a reader
meets it rather than left to be discovered.

packaging/debian/control.in

@@ -0,0 +1,32 @@
+Package: hyprcosmic
+Version: @VERSION@
+Architecture: amd64
+Maintainer: dingo <[email protected]>
+Section: x11
+Priority: optional
+Homepage: https://github.com/outbackdingo/hyprcosmic
+Installed-Size: @INSTALLED_SIZE@
+Depends: @SHLIB_DEPENDS@
+Recommends: waybar, rofi
+Suggests: fonts-hack-ttf, qt5ct
+Conflicts: cosmic-comp, cosmic-session
+Provides: cosmic-comp, cosmic-session
+Replaces: cosmic-comp, cosmic-session
+Description: COSMIC configured in Hyprland's idiom, with a HyDE shell
+ HyprCosmic is a fork of the COSMIC desktop that takes its configuration in
+ Hyprland's idiom and wears a HyDE-style shell.
+ .
+ A single ~/.config/hyprcosmic/cosmic.conf -- with general { } blocks, bind =
+ lines and $variables -- is compiled into COSMIC's own configuration tree by
+ cosmic-conf. The file is the source of truth: keys it names are applied at
+ every login over whatever the settings UI last stored, and keys it does not
+ name are left alone.
+ .
+ The shell is waybar, rofi and awww in place of cosmic-panel, cosmic-launcher
+ and cosmic-bg, and HyDE themes are imported directly. The compositor is
+ COSMIC's, with a Hyprland-compatible IPC socket so that HyDE's scripts and
+ waybar's hyprland modules work unmodified.
+ .
+ This package replaces the distribution's COSMIC. It installs both session
+ entries, so the greeter offers a stock COSMIC shell as well as the HyDE one,
+ both served by these binaries.