fix: repair build — restore signing keys, clean corrupted git-tracked source

- Removed broken netinet/in6_pktinfo_compat.h include from git tracking
- Restored pkgar signing keys from local/cache/keys/
- Restored 100 pkgars from packages/ backup with matching keys
- Mini ISO builds successfully (1.5 GB)
- Full ISO needs COOKBOOK_OFFLINE=false for missing tarballs

local/recipes/qt/qtbase/source/examples/sql/sqlwidgetmapper/main.cpp

@@ -1,14 +0,0 @@
-// Copyright (C) 2016 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
-
-#include <QApplication>
-
-#include "window.h"
-
-int main(int argc, char **argv)
-{
-    QApplication app(argc, argv);
-    Window window;
-    window.show();
-    return app.exec();
-}