PlasmaZones 1.15.10

Fixed

• Login freeze persisted despite v1.15.9 batching (fixes #200): The v1.15.9 deferred batch approach still blocked because each batch made synchronous D-Bus round-trips whose replies stalled for ~25s while kglobalaccel processed key grabs (QTBUG-34698). Replaced with true async D-Bus. setDefaultShortcut() registers actions synchronously (fast, no key grabbing), then setShortcutKeys calls fire via QDBusPendingCallWatcher so the event loop never blocks on key grabbing.