fix(quickshell): clear launcher search field on reopen

The host's Loader keeps the LauncherPopout instance alive across
close/reopen, so a stale query from the previous open lingered in the
search field. Reset the input in focusFirst() (called by PopoutHost on
every open); the text reset cascades through onTextChanged -> query ->
currentIndex.

defaults/xdg/quickshell/moonarch/LauncherPopout.qml

@@ -43,7 +43,10 @@ Item {
     }
 
     // The host focuses this on open (PopoutHost's focusFirst path) — hand focus to the search field.
+    // Clear first: the host's Loader keeps this instance alive across close/reopen, so a stale query
+    // from the previous open would otherwise linger (text reset feeds onTextChanged -> query -> currentIndex).
     function focusFirst() {
+        input.text = "";
         input.forceActiveFocus();
     }