Launch apps in their own scope instead of the compositor's cgroup (#6541)

* Launch apps in their own scope instead of the compositor's cgroup

The launcher ran desktop entries through gtk-launch, so the app inherited
quickshell's cgroup, which belongs to wayland-wm@hyprland.desktop.service.
A kernel OOM kill there fails the compositor unit and tears down the whole
session, dropping the user at SDDM with every window lost. A single runaway
app took the desktop down three times in one afternoon.

Route launches through uwsm-app so each app gets its own scope under
app-graphical.slice. A runaway app now fails its own scope and the session
keeps running.

The post-install launches had the same inheritance bug in a milder form,
where the app landed in the installer terminal's scope and died with it.
0aedef58 patched that with setsid, which detaches the session but leaves
cgroup membership behind. A scope fixes it properly.

* Detach post-install app launches

* Preserve desktop entry launch compatibility

---------

Co-authored-by: David Heinemeier Hansson <david@hey.com>

test/shell.d/app-search-test.sh

@@ -99,9 +99,9 @@ assert(
 )
 
 assert(
-  /function launch\(desktopId, name\) \{[\s\S]*?gtk-launch[\s\S]*?\n  \}/.test(appLibraryQml) &&
-    appLibraryQml.includes('Util.execDetached("gtk-launch "'),
-  'app library runs desktop entry launch through the shell'
+  /function launch\(desktopId, name\) \{[\s\S]*?uwsm-app[\s\S]*?\n  \}/.test(appLibraryQml) &&
+    appLibraryQml.includes('Util.execDetached("uwsm-app -- gtk-launch "'),
+  'app library launches desktop entries through gtk-launch in their own scope'
 )
 
 assert(

test/shell.d/desktop-entry-launch-test.sh

@@ -0,0 +1,99 @@
+#!/bin/bash
+
+set -euo pipefail
+
+source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
+
+test_tmp=$(mktemp -d)
+trap 'rm -rf "$test_tmp"' EXIT
+
+mock_bin="$test_tmp/bin"
+test_home="$test_tmp/home"
+mkdir -p "$mock_bin" "$test_home"
+
+cat >"$mock_bin/omarchy-pkg-add" <<'SH'
+#!/bin/bash
+printf 'pkg:%s\n' "$*" >>"$OMARCHY_TEST_LOG"
+exit "${OMARCHY_TEST_PKG_STATUS:-0}"
+SH
+
+for command in omarchy-pkg-aur-add omarchy-install-emacs omazed omarchy-theme-set-vscode omarchy-install-gaming-gpu-lib32; do
+  cat >"$mock_bin/$command" <<'SH'
+#!/bin/bash
+exit 0
+SH
+done
+
+cat >"$mock_bin/setsid" <<'SH'
+#!/bin/bash
+printf 'launch:%s\n' "$*" >>"$OMARCHY_TEST_LOG"
+SH
+
+cat >"$mock_bin/omarchy-launch-floating-terminal-with-presentation" <<'SH'
+#!/bin/bash
+printf '%s\n' "$1" >"$OMARCHY_TEST_PRESENTATION"
+SH
+
+chmod +x "$mock_bin"/*
+
+export HOME="$test_home"
+export OMARCHY_TEST_LOG="$test_tmp/launch.log"
+export OMARCHY_TEST_PRESENTATION="$test_tmp/presentation"
+export PATH="$mock_bin:$PATH"
+
+wait_for_launch() {
+  local expected="$1"
+
+  for ((attempt = 0; attempt < 100; attempt++)); do
+    grep -Fxq "$expected" "$OMARCHY_TEST_LOG" && return 0
+    sleep 0.01
+  done
+
+  return 1
+}
+
+assert_detached_installer_launch() {
+  local script="$1"
+  local desktop_id="$2"
+
+  : >"$OMARCHY_TEST_LOG"
+  bash "$ROOT/bin/$script"
+
+  wait_for_launch "launch:uwsm-app -- gtk-launch $desktop_id" ||
+    fail "$script launches its desktop entry through gtk-launch in a UWSM scope"
+  grep -Fqx "setsid uwsm-app -- gtk-launch $desktop_id >/dev/null 2>&1 &" "$ROOT/bin/$script" ||
+    fail "$script detaches its scoped desktop-entry launch"
+  pass "$script detaches its scoped desktop-entry launch"
+}
+
+assert_detached_installer_launch omarchy-install-editor-emacs emacsclient
+assert_detached_installer_launch omarchy-install-editor-vscode code
+assert_detached_installer_launch omarchy-install-editor-zed dev.zed.Zed
+assert_detached_installer_launch omarchy-install-gaming-heroic heroic
+assert_detached_installer_launch omarchy-install-gaming-steam steam
+
+bash "$ROOT/bin/omarchy-install-and-launch" "Example App" "alpha beta" "Disk Usage"
+presentation_command=$(<"$OMARCHY_TEST_PRESENTATION")
+
+[[ $presentation_command == *'echo Installing\ Example\ App...;'* ]] ||
+  fail "generic installer shell-quotes the display name" "$presentation_command"
+[[ $presentation_command == *'omarchy-pkg-add alpha beta && (setsid uwsm-app -- gtk-launch Disk\ Usage >/dev/null 2>&1 &)'* ]] ||
+  fail "generic installer waits for packages and detaches only the scoped launch" "$presentation_command"
+pass "generic installer waits for packages and detaches only the scoped launch"
+
+: >"$OMARCHY_TEST_LOG"
+bash -c "$presentation_command"
+grep -Fxq 'pkg:alpha beta' "$OMARCHY_TEST_LOG" ||
+  fail "generic installer passes every package to the package helper"
+wait_for_launch 'launch:uwsm-app -- gtk-launch Disk Usage' ||
+  fail "generic installer preserves a desktop ID containing spaces"
+pass "generic installer preserves a desktop ID containing spaces"
+
+: >"$OMARCHY_TEST_LOG"
+if OMARCHY_TEST_PKG_STATUS=1 bash -c "$presentation_command"; then
+  fail "generic installer propagates package installation failure"
+fi
+if grep -q '^launch:' "$OMARCHY_TEST_LOG"; then
+  fail "generic installer does not launch after package installation failure"
+fi
+pass "generic installer does not launch after package installation failure"