feat(slock): implement ext_session_lock_v1 backend

note: did not run lints or fully test yet

src/wayland/session_lock/manager.hpp

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <qtclasshelpermacros.h>
+#include <qwayland-ext-session-lock-v1.h>
+#include <qwaylandclientextension.h>
+
+#include "lock.hpp"
+
+class QSWaylandSessionLockManager
+    : public QWaylandClientExtensionTemplate<QSWaylandSessionLockManager>
+    , public QtWayland::ext_session_lock_manager_v1 {
+public:
+	QSWaylandSessionLockManager();
+	~QSWaylandSessionLockManager() override;
+	Q_DISABLE_COPY_MOVE(QSWaylandSessionLockManager);
+
+	// Create a new session lock if there is no currently active lock, otherwise null.
+	QSWaylandSessionLock* acquireLock();
+	[[nodiscard]] bool isLocked() const;
+
+	static bool sessionLocked();
+
+private:
+	QSWaylandSessionLock* active = nullptr;
+
+	friend class QSWaylandSessionLock;
+};