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/forum.h

@@ -0,0 +1,72 @@
+/*
+    This file is part of KDE.
+
+    SPDX-FileCopyrightText: 2011 Laszlo Papp <djszapi@archlinux.us>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#ifndef ATTICA_FORUM_H
+#define ATTICA_FORUM_H
+
+#include "attica_export.h"
+
+#include "topic.h"
+
+#include <QDateTime>
+#include <QSharedDataPointer>
+#include <QUrl>
+
+namespace Attica
+{
+
+/**
+ * @class Forum forum.h <Attica/Forum>
+ *
+ * Represents a forum.
+ */
+class ATTICA_EXPORT Forum
+{
+public:
+    typedef QList<Forum> List;
+    class Parser;
+
+    Forum();
+    Forum(const Forum &other);
+    Forum &operator=(const Forum &other);
+    ~Forum();
+
+    void setId(const QString &id);
+    QString id() const;
+
+    void setName(const QString &name);
+    QString name() const;
+
+    void setDescription(const QString &description);
+    QString description() const;
+
+    void setDate(const QDateTime &date);
+    QDateTime date() const;
+
+    void setIcon(const QUrl &icon);
+    QUrl icon() const;
+
+    void setChildCount(const int childCount);
+    int childCount() const;
+
+    void setTopics(const int topics);
+    int topics() const;
+
+    void setChildren(QList<Forum> comments);
+    QList<Forum> children() const;
+
+    bool isValid() const;
+
+private:
+    class Private;
+    QSharedDataPointer<Private> d;
+};
+
+}
+
+#endif