plasma-desktop: depend on the X11 libraries; disable doc generation

feature_summary aborted on two REQUIRED packages:

 * X11 -- "Required for building the X11 based workspace". The libraries exist
   (promoted out of wip and building), but plasma-desktop did not depend on
   them, so they were absent from its sysroot and cmake reported X11 missing.
   Exactly the gap libxcb had earlier. Added libx11, libxext, libxfixes, libxi,
   libxrender, libxau, libxdmcp.

   This is where providing the real X11 stack pays off: the alternative was
   patching plasma-desktop to stop requiring X11 at all, which is a much larger
   and more invasive change than declaring a dependency that already builds.

 * KF6DocTools -- not ported, and REQUIRED only because BUILD_DOC defaults ON.
   Disabled: this drops generated handbook pages, not functionality; every
   settings module still builds.

local/recipes/kde/plasma-desktop/recipe.toml

@@ -18,6 +18,17 @@ dependencies = [
     # xcb and xcb-shm; IMAGE comes from xcb-util-image (which needs xcb-util).
     # Needed even on Wayland -- KDE's XWayland integration and Qt's xcb
     # platform plugin both reference it.
+    # find_package(X11) is REQUIRED ("Required for building the X11 based
+    # workspace"). These are promoted and building; without them in this
+    # recipe's sysroot cmake reports X11 as missing even though the libraries
+    # exist -- the same gap libxcb had.
+    "libx11",
+    "libxext",
+    "libxfixes",
+    "libxi",
+    "libxrender",
+    "libxau",
+    "libxdmcp",
     "libxcb",
     "xcb-util",
     "xcb-util-image",
@@ -125,6 +136,9 @@ sed -i 's|if (NOT EXISTS "${CMAKE_SYSROOT}/${XKBDIR}")|if (NOT EXISTS "${CMAKE_S
 
 python3 "${COOKBOOK_ROOT}/local/scripts/gate-kx11extras.py" "${COOKBOOK_SOURCE}"
 
+# BUILD_DOC=OFF -- KF6DocTools is REQUIRED when docs are on and is not ported.
+# This drops generated handbook pages only; every settings module still builds.
+#
 # BUILD_KCM_MOUSE_X11=OFF / BUILD_KCM_TOUCHPAD_X11=OFF -- drop the X11-SESSION
 # input backends only. Both KCMs keep their KWin+Wayland backends
 # (BUILD_KCM_MOUSE_KWIN_WAYLAND / BUILD_KCM_TOUCHPAD_KWIN_WAYLAND stay ON),
@@ -158,6 +172,7 @@ python3 "${COOKBOOK_ROOT}/local/scripts/gate-kx11extras.py" "${COOKBOOK_SOURCE}"
 #
 # Tracked for a real port; turn back ON in the same change that lands libwacom.
 cmake "${COOKBOOK_SOURCE}" \
+    -DBUILD_DOC=OFF \
     -DBUILD_KCM_TABLET=OFF \
     -DBUILD_KCM_MOUSE_X11=OFF \
     -DBUILD_KCM_TOUCHPAD_X11=OFF \