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/privatedataparser.cpp

@@ -0,0 +1,41 @@
+/*
+    This file is part of KDE.
+
+    SPDX-FileCopyrightText: 2008 Cornelius Schumacher <schumacher@kde.org>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#include "privatedataparser.h"
+
+using namespace Attica;
+
+PrivateData PrivateData::Parser::parseXml(QXmlStreamReader &xml)
+{
+    PrivateData data;
+    QString key;
+
+    // TODO: when we get internet and some documentation
+    while (!xml.atEnd()) {
+        xml.readNext();
+
+        if (xml.isStartElement()) {
+            if (xml.name() == QLatin1String("key")) {
+                key = xml.readElementText();
+            } else if (xml.name() == QLatin1String("value")) {
+                data.setAttribute(key, xml.readElementText());
+            } else if (xml.name() == QLatin1String("timestamp")) {
+                data.setTimestamp(key, QDateTime::fromString(xml.readElementText(), Qt::ISODate));
+            }
+        } else if (xml.isEndElement() && (xml.name() == QLatin1String("data") || xml.name() == QLatin1String("user"))) {
+            break;
+        }
+    }
+
+    return data;
+}
+
+QStringList PrivateData::Parser::xmlElement() const
+{
+    return QStringList(QStringLiteral("privatedata"));
+}