fix: KF6Attica recipe, kf6-knewstuff Attica dep, topo-sort cycle error

- Created kf6-attica recipe (minimal core library build providing
  KF6::Attica cmake target, needed by kf6-knewstuff). v6.10.0,
  QML/tests/examples disabled.
- Added kf6-attica to redbear-full.toml config, integrate-redbear.sh
  symlink, and recipes/kde/ symlink.
- Fixed kf6-knewstuff: removed stale find_package(KF6Attica)
  suppression; added kf6-attica as dependency. Now publishes
  to repo (core-only build produces empty package — upstream
  code structure yields no libs with QtQuick/widgets/tools off).
- Cookbook topo-sort: changed cycle fallback from silent
  Ok(recipes) to Err(Recursion) — surfaces dependency graph
  bugs instead of hiding them.
- Fixed stale QtNetwork comment: QtNetwork IS enabled in qtbase
  since 2026-04-29 (relibc DNS resolver hardened).
- Verified: kf6-attica builds, kf6-knewstuff publishes to repo

local/recipes/kde/kf6-attica/source/src/privatedata.cpp

@@ -0,0 +1,73 @@
+/*
+    This file is part of KDE.
+
+    SPDX-FileCopyrightText: Martin Sandsmark <martin.sandsmark@kde.org>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#include "privatedata.h"
+
+#include <QStringList>
+
+using namespace Attica;
+
+class Q_DECL_HIDDEN PrivateData::Private : public QSharedData
+{
+public:
+    QMap<QString, QString> m_attributes;
+    QMap<QString, QDateTime> m_attributesTimestamp;
+
+    Provider *m_provider;
+
+    Private()
+        : m_provider(nullptr)
+    {
+    }
+};
+
+PrivateData::PrivateData()
+    : d(new Private)
+{
+}
+
+PrivateData::PrivateData(const PrivateData &other)
+    : d(other.d)
+{
+}
+
+PrivateData &PrivateData::operator=(const Attica::PrivateData &other)
+{
+    d = other.d;
+    return *this;
+}
+
+PrivateData::~PrivateData()
+{
+}
+
+void PrivateData::setAttribute(const QString &key, const QString &value)
+{
+    d->m_attributes[key] = value;
+    d->m_attributesTimestamp[key] = QDateTime::currentDateTime();
+}
+
+QString PrivateData::attribute(const QString &key) const
+{
+    return d->m_attributes[key];
+}
+
+QDateTime PrivateData::timestamp(const QString &key) const
+{
+    return d->m_attributesTimestamp[key];
+}
+
+QStringList PrivateData::keys() const
+{
+    return d->m_attributes.keys();
+}
+
+void PrivateData::setTimestamp(const QString &key, const QDateTime &when)
+{
+    d->m_attributesTimestamp[key] = when;
+}