apt and dnf install TuiCode from a package attached to each release #416

Context

A Debian, Ubuntu or Fedora user expects to install software with apt or dnf so the system knows it's there and its dependencies are declared. This task attaches .deb and .rpm packages for x64 and arm64 to every release. Pitch: #44. Needs #414 merged first, so the packages hold a binary that starts on the distros they target.

Acceptance criteria

• Every release from now on has tuicode_<version>_amd64.deb, tuicode_<version>_arm64.deb, tuicode-<version>-1.x86_64.rpm and tuicode-<version>-1.aarch64.rpm attached, beside the tarballs.
• sudo apt install ./tuicode_<version>_amd64.deb on Debian 12 and Ubuntu 22.04, and sudo dnf install <release URL of the .rpm> on Fedora, install tuicode onto PATH, and tuicode starts.
• dpkg -l tuicode / rpm -q tuicode show the release's version, and installing a newer package upgrades it in place.
• Installing pulls in what the binary needs, and recommends wl-clipboard or xclip for copy where the terminal refuses OSC 52.
• The package carries the licence and third-party notices, and uninstalling removes everything it installed.
• The README's Linux install block shows the apt and dnf commands, and CONTRIBUTING's release section and diagram include the packages.

Tests

• In the release run, build both formats for both architectures from the same binaries as the tarballs, with nfpm (or similar) and a template kept in packaging/.
• A job in the release run that installs each package in a clean container (debian:12, ubuntu:22.04, fedora, per architecture) and runs tuicode --smoke; a failure stops the release before publishing, like a failed build.
• A way to build and check the packages in CI without cutting a release, so a PR that breaks packaging fails there.

Out of scope

• A hosted apt or dnf repository, signing, or auto-update (the apt repo is its own task).
• Changes to a-team's shared publish workflow beyond attaching extra assets, if that's needed at all.
• The AUR (On Arch I can't install or update TuiCode with yay #383), Flatpak, Snap, Nix.