make spawned apps survive att_menu termination

README.md

@@ -242,6 +242,15 @@ components/ToggleSwitch.qml   On/off switch
 - Quickshell's `DesktopEntry.execute()` intentionally ignores `Terminal=true`
   and does not strip `Exec` field codes, so entries would be launched with a
   literal `%U` argument. `services/AppLauncher.qml` handles both instead.
+- `Quickshell.execDetached` detaches a launched app from the panel *process*, but
+  not from its control group. Run as a systemd user unit — which is how tablet
+  mode starts the panel — stopping the unit signals every process in the group,
+  so the panel would take down every app it had ever launched. `AppLauncher` puts
+  each app in a transient scope of its own with `systemd-run --user --scope`, and
+  only when `INVOCATION_ID` says the panel is a unit: started from a shell or by
+  the compositor it shares the session's group, where wrapping buys nothing. A
+  scope rather than a service, so the app inherits the environment it needs —
+  `WAYLAND_DISPLAY` above all.
 - Icons are resolved through the Qt icon theme, falling back to the last segment
   of a reverse-DNS app id (`org.qutebrowser.qutebrowser` → `qutebrowser`), then
   to a lettered tile. The packaged build adds Adwaita and hicolor to

services/AppLauncher.qml

@@ -12,6 +12,26 @@ import qs.config
 Singleton {
     id: root
 
+    // Set only when att_menu itself was started by systemd, which is the one
+    // case where the control group is worth escaping. Started from a shell or
+    // by the compositor the panel shares the session's group, and wrapping
+    // would buy nothing.
+    readonly property bool inSystemdUnit: !!Quickshell.env("INVOCATION_ID")
+
+    // Moves a launched app into a transient scope of its own, outside att_menu's
+    // control group. Stopping a systemd unit signals every process in its group
+    // and execDetached's fork does not leave it, so without this the panel takes
+    // down everything it ever launched — which is what happens each time tablet
+    // mode ends and the unit is stopped.
+    //
+    // A scope, not a service: the app keeps the environment, working directory
+    // and stdio it was given, so WAYLAND_DISPLAY and friends still reach it.
+    // The exec'd shell leaves no process of its own behind, and passing the app
+    // as "$@" keeps its arguments intact. systemd-run is only assumed to be on
+    // PATH when it is actually there — the panel runs on systems packaged
+    // without it too.
+    readonly property var scopeWrapper: ["sh", "-c", "command -v systemd-run >/dev/null 2>&1 && exec systemd-run --user --scope --collect --quiet -- \"$@\"; exec \"$@\"", "att_menu"]
+
     function withoutFieldCodes(command: var): var {
         const out = [];
 
@@ -37,7 +57,7 @@ Singleton {
 
         const argv = entry.runInTerminal ? [...Config.terminal, ...command] : command;
         const options = {
-            command: argv
+            command: root.inSystemdUnit ? [...root.scopeWrapper, ...argv] : argv
         };
 
         if (entry.workingDirectory)