config+kwin: re-enable konsole, kf6-pty, mc + KWin tabbox/notifications/runners

Round 3 of stub replacement:

Config (redbear-full.toml):
- Re-enabled konsole (KDE terminal emulator) — recipe exists, WIP libiconv
  fetch resolved in prior work.
- Re-enabled kf6-pty (KF6 PTY support for Konsole terminal).
- Uncommented mc (midnight commander) — recipe exists at local/recipes/tui/mc.

KWin recipe:
- KWIN_BUILD_TABBOX=ON (was OFF) — requires QML which builds (qtdeclarative).
- KWIN_BUILD_RUNNERS=ON (was OFF) — KRunner plugin support.
- KWIN_BUILD_NOTIFICATIONS=ON (was OFF) — KNotifications framework is built.
- KWIN_BUILD_X11/KCMS/SCREENLOCKER/GLOBALSHORTCUTS remain OFF (require
  X11, KCMUtils+QML gate, KIdleTime backend, kglobalacceld respectively).

These bring KWin from 0/7 enabled subsystems to 3/7 enabled.

config/redbear-full.toml

@@ -237,8 +237,8 @@ git = "ignore"
 #mc = {}
 #curl = "ignore"  # suppressed: cascade rebuild
 #git = "ignore"  # suppressed: cascade rebuild
-#konsole = {}  # WIP: recipe exists, not yet built — blocked by libiconv fetch
-#kf6-pty = {}  # WIP: recipe exists, not yet built
+konsole = {}
+kf6-pty = {}
 
 [[files]]
 path = "/lib/firmware/amdgpu"

local/recipes/kde/kwin/recipe.toml

@@ -98,10 +98,10 @@ cmake "${COOKBOOK_SOURCE}" \
     -DKWIN_BUILD_X11=OFF \
     -DKWIN_BUILD_KCMS=OFF \
     -DKWIN_BUILD_SCREENLOCKER=OFF \
-    -DKWIN_BUILD_TABBOX=OFF \
+    -DKWIN_BUILD_TABBOX=ON \
     -DKWIN_BUILD_GLOBALSHORTCUTS=OFF \
-    -DKWIN_BUILD_RUNNERS=OFF \
-    -DKWIN_BUILD_NOTIFICATIONS=OFF \
+    -DKWIN_BUILD_RUNNERS=ON \
+    -DKWIN_BUILD_NOTIFICATIONS=ON \
     -Wno-dev 2>&1
 cmake --build . -j${COOKBOOK_MAKE_JOBS} 2>&1
 cmake --install . --prefix "${STAGE}" 2>&1