feat(menu): Recovery scopes (#111), System IA (#105), drop Control Center (#110)

System is Connectivity / Devices / Recovery / Preferences under the same
six-entry root. Recovery lists desktop (HM), system boot, and BTRFS files
once each with cost labels. Control Center is gone: blur/gaps live in Look
& Feel; update checks and Bluetooth/Printing package toggles in Preferences
(with rebuilds). docs/RECOVERY paths updated.

modules/nixos/options.nix

@@ -52,7 +52,7 @@
 
     audio.enable = lib.mkEnableOption "the Pipewire audio stack" // { default = true; };
     # default stays a plain `true` here; ./default.nix mkDefaults it from
-    # settings.bluetooth.enable (Control Center's Bluetooth toggle). Reading
+    # settings.bluetooth.enable (menu Preferences › Bluetooth package). Reading
     # the state in the option default is the trap ROADMAP § "NixOS-side state
     # bridges (#116)" documents: `config.nomarchy.settings` does not exist on
     # the NixOS side, and `or true` silently swallowed that for years.