Give a reconnected display the arrangement it had

hypr/monitors.lua applies the stored per-output entries when the
compositor reads its config, and never again. A monitor plugged in an
hour later got the compositor's automatic placement instead of the
position, scale and rotation this machine was told to use, and the
only way back was to open Settings and apply it again. Docking should
not cost you your desk.

Deliberately not a confirmed transaction. applyLayout arms a fifteen
second countdown because it is about to show you something you might
not be able to undo; this restores a layout you already confirmed, on
hardware you already had, and a countdown would be asking you to
re-approve your own decision every time you sat down.

It refuses rather than guesses when the stored mode is one the
connected panel does not offer -- DP-1 on one dock is not DP-1 on
another -- and when the surviving layout would name no primary. Both
land on the compositor's automatic placement plus a toast that opens
the Displays page, which is recoverable; silence would not be. That
toast needed a new open-settings verb in StatusEvents, whose page name
goes through ShellState's existing allow-list.

The decision is split from the action as plannedRestore so it can be
tested without driving a real compositor, and the harness sets topology
and stored arrangement in one call because a real query landing between
two would replace the fixture. Both fixtures travel base64: qs ipc call
splits a JSON array of several objects into one argument per object,
so a two-monitor fixture was arriving as an extra argument.

config/dot/quickshell/services/StatusEvents.qml

@@ -91,6 +91,11 @@ Singleton {
             ShellState.open("activity");
         } else if (action === "open-path" && data) {
             Quickshell.execDetached(["xdg-open", data]);
+        } else if (action === "open-settings" && data) {
+            // The page name is checked by ShellState's own allow-list, so an
+            // event naming a page that does not exist lands on Home rather
+            // than nowhere.
+            ShellState.openSettings(data);
         }
     }