fix: declare kwin's missing REQUIRED deps; gate the Canberra-only plugin

kwin's CMakeLists issues find_package/pkg_check_modules REQUIRED for
several packages that are in the config and built but were never declared
as deps, so they were never staged into kwin's sysroot: libxcvt,
libdisplay-info, kglobalacceld, libinput, lcms2. Audited the CMakeLists
for REQUIRED names and cross-checked against recipes that exist, rather
than adding them one failed configure at a time.

KF6_HOST_TOOLING must point at the HOST's system KF6 (/usr/lib/cmake), as
konsole already does. src/wayland/tools needs a native Qt/KF6 prefix;
pointing it at build/qt-host-build instead fails differently, because that
tree carries Qt host tooling but no KF6, and KF6AuthConfig /
KF6KCMUtilsConfig then fail their include().

systembell: TEMPORARY DEBT, narrowly scoped and documented at the call
site. It is the only consumer of Canberra in KWin, yet
find_package(Canberra REQUIRED) is ungated, so one optional audible-bell
plugin blocks the whole compositor. The in-tree WIP libcanberra recipe
depends on gtk3 and is itself marked 'no audio backend supported'; a local
recipe using --disable-gtk3 plus the null backend is the intended fix.
Visual bell and every other effect are unaffected.

local/recipes/kde/kwin/recipe.toml

@@ -49,6 +49,13 @@ dependencies = [
     "vulkan-loader",
     "plasma-wayland-protocols",
     "libepoxy",
+    # pkg_check_modules(... REQUIRED) in kwin's CMakeLists: present in the
+    # config and built, but never staged into kwin's sysroot without a dep.
+    "libxcvt",
+    "libinput",
+    "lcms2",
+    "libdisplay-info",
+    "kglobalacceld",
     "libudev",
     "wayland-protocols",
     "redbear-compositor",
@@ -75,6 +82,26 @@ sed -i '/include(ECMQmlModule)/s/^/#/' "${COOKBOOK_SOURCE}/CMakeLists.txt" 2>/de
 # Remove Qt components not available in cross-build
 sed -i '/^    UiTools$/d' "${COOKBOOK_SOURCE}/CMakeLists.txt"
 
+# TEMPORARY DEBT -- systembell (audible bell) is the ONLY consumer of Canberra
+# in KWin (src/plugins/systembell/*). kwin's find_package(Canberra REQUIRED) is
+# ungated, so the whole compositor fails to configure over one optional plugin.
+#
+# The proper fix is to port libcanberra, and it is NOT done here because the
+# in-tree WIP recipe (recipes/wip/libs/audio/libcanberra) depends on gtk3 --
+# an enormous port for an audio bell -- and is itself marked "no audio backend
+# supported". A local recipe using upstream's --disable-gtk3 plus the null
+# backend is the intended route; until then this drops one non-essential
+# plugin, not compositor functionality.
+#
+# Scope: audible system bell only. Visual bell and all other KWin effects are
+# unaffected. Remove BOTH seds once libcanberra is ported.
+# Idempotent: once commented, ^add_subdirectory no longer matches; the
+# find_package line is rewritten to a form that no longer matches REQUIRED.
+sed -i 's/^add_subdirectory(systembell)/#add_subdirectory(systembell)/' \
+    "${COOKBOOK_SOURCE}/src/plugins/CMakeLists.txt" 2>/dev/null || true
+sed -i 's/^find_package(Canberra REQUIRED)/find_package(Canberra)/' \
+    "${COOKBOOK_SOURCE}/CMakeLists.txt" 2>/dev/null || true
+
 rm -f CMakeCache.txt
 rm -rf CMakeFiles
 
@@ -96,6 +123,7 @@ cmake "${COOKBOOK_SOURCE}" \
     -DKF_SKIP_PO_PROCESSING=ON \
     -DCMAKE_TOOLCHAIN_FILE="${COOKBOOK_ROOT}/local/recipes/qt/redox-toolchain.cmake" \
     -DQT_HOST_PATH="${HOST_BUILD}" \
+    -DKF6_HOST_TOOLING=/usr/lib/cmake \
     -DCMAKE_INSTALL_PREFIX=/usr \
     -DCMAKE_BUILD_TYPE=Release \
     -DCMAKE_PREFIX_PATH="${COOKBOOK_SYSROOT}" \