feat(menu,install): #50 one-liners + record #46 V2 install pass

#50: Bluetooth menu row + handler self-gate on `command -v
blueman-manager` (no-op when bluetooth is off, like Printers); Control
Center rollback list /tmp/nomarchy-gens → mktemp; usbutils on the
nomarchy-install PATH (fingerprint lsusb probe); export
nomarchy-doctor/control-center/battery-notify as flake packages.
Verified V0 (flake check) + V1 (packages, installer, HM generation build).

Also records #46: the swap=0 + unattended-LUKS fail-closed contracts
(208b8d4) V2-verified via a headless two-variant install — fail-closed
exits before wipe with the disk blank; swap=0 installs with no @swap
subvol and boots to a themed desktop. Both items removed from NEXT.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

flake.nix

@@ -115,6 +115,11 @@
       packages.${system} = {
         nomarchy-theme-sync = pkgs.nomarchy-theme-sync;
         nomarchy-install = nomarchyInstall;
+        # Overlay tools exported for `nix build .#nomarchy-doctor` etc.
+        # (maintainer/CI convenience — modules install them via the overlay).
+        nomarchy-doctor = pkgs.nomarchy-doctor;
+        nomarchy-control-center = pkgs.nomarchy-control-center;
+        nomarchy-battery-notify = pkgs.nomarchy-battery-notify;
         default = pkgs.nomarchy-theme-sync;
       };