feat: The Steamify shortcut opens the app

Steamify CachyOS on the desktop and in the launcher starts the newest app
(in Konsole the first time, while PySide6 still has to be installed); the
terminal menu is Steamify Terminal in the launcher. A shortcut from before
2.0.1 is ticked in the menu, so a normal run replaces it. steamify-app.sh
leaves the shortcut's launcher entry (same id) alone.

AGENTS.md

@@ -161,9 +161,14 @@ gamescope and the Plasma desktop. Primary target: the Valve Steam Machine
   now? [Y/n]" (`quit_prompt`): `n` goes back to the menu, the next `q` asks
   again. Scripted input that runs out quits without restarting (never
   restart on EOF: `ask_yn` would take its default).
-- Steamify shortcut (`launcher`): the icon runs `curl | bash` of
-  `releases/latest/download/steamify.sh` in Konsole, so it's
-  always the newest release. Its icon, `assets/steam-gaming-settings.svg`
+- Steamify shortcut (`launcher`): "Steamify CachyOS" (desktop and launcher,
+  id `steamify-ui.desktop`, the app's own id) runs `curl | bash` of
+  `releases/latest/download/steamify-app.sh` without a terminal (in Konsole
+  only while PySide6 is missing, for sudo); "Steamify Terminal" (launcher)
+  runs `steamify.sh` in Konsole. Both always the newest release. The entry
+  has `X-Steamify-Shortcut=true`: steamify-app.sh doesn't overwrite it, and
+  disable only removes it then. A pre-2.0.1 shortcut (terminal only) is
+  ticked by `launcher_repair`. Its icon, `assets/steam-gaming-settings.svg`
   (Valve's GPL-2.0 return icon with a gear), is a release asset too, and is
   downloaded from there (Steam's icon if that fails). Desktop files are
   written with their mode already set (`install_executable`): Plasma opens a