config: re-enable mc (midnight commander)

The mc recipe exists at local/recipes/tui/mc. It was the last
remaining commented-out package in redbear-full.toml.

All previously commented-out packages are now re-enabled:
- libxkbcommon, xkeyboard-config (keyboard layouts)
- kirigami (KDE QML framework)
- konsole (KDE terminal)
- kf6-pty (PTY support)
- kde-cli-tools (KDE CLI tools)
- mc (midnight commander)

config/redbear-full.toml

@@ -234,7 +234,7 @@ cosmic-icons = "ignore"
 cosmic-term = "ignore"
 curl = "ignore"
 git = "ignore"
-#mc = {}
+mc = {}
 #curl = "ignore"  # suppressed: cascade rebuild
 #git = "ignore"  # suppressed: cascade rebuild
 konsole = {}