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

config/redbear-full.toml

@@ -53,11 +53,14 @@ qt6-wayland-smoke = {}
 
 # KF6 Frameworks — explicit real-build surface in alphabetical order
 # kirigami: core-only build (QML disabled), needed as build-dep for plasma-framework
-# kf6-kio: honest KIOCORE_ONLY build (source-local QtNetwork compat headers)
-kirigami = {}
+# kf6-kio: honest KIOCORE_ONLY build (QtNetwork now available in qtbase)
+kirigami = "ignore"
 kf6-kio = {}
+kf6-knewstuff = {}
+kf6-kwallet = {}
 
 kdecoration = {}
+kf6-attica = {}
 kf6-karchive = {}
 kf6-kauth = {}
 kf6-kbookmarks = {}