feat(menu): printer setup — system-config-printer in the System submenu

A `nomarchy-menu printers` entry opens system-config-printer (the CUPS
admin GUI), mirroring the bluetooth/blueman pattern: the printing service
ships the package via environment.systemPackages and the menu execs it,
self-gated on the system-config-printer binary so the entry appears only
when nomarchy.services.printing is on. No direct keybind (rare one-off).

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

docs/ROADMAP.md

@@ -85,6 +85,18 @@ how to override it. Items marked ✓ are shipped.
     so it'd mean adopting a new secret manager. Revisit if that changes.
   - Also: menu search is now **case-insensitive fuzzy** (`matching = fuzzy`,
     `sorting-method = fzf`) across every module + the launcher.
+- ✓ **Printer setup menu module:** a `nomarchy-menu printers` entry in the
+  **System** submenu opens **system-config-printer** (the CUPS admin GUI —
+  discovery, drivers/PPDs, options, test page), mirroring the bluetooth/blueman
+  pattern: the printing service ships the package (`environment.systemPackages`)
+  and the menu execs it, self-gated on the `system-config-printer` binary so
+  the entry appears only when `nomarchy.services.printing` is on. No direct
+  `SUPER+CTRL` bind — printer setup is a rare one-off, not a frequent utility
+  (left out deliberately; easy to add). Chose the GUI over a rofi-native
+  `lpadmin` flow (driver/PPD picking is impractical in rofi) and the CUPS web
+  UI (an unthemed browser page). Validated: the generated menu script's
+  `bash -n` build check passes, and an eval confirms printing-on puts
+  system-config-printer in `systemPackages`. Pending an on-machine check.
 - **Theme parity with legacy:** summer-day/night now carry their legacy
   bar layouts as `waybar.jsonc` whole-swaps (adapted: dead legacy script
   modules dropped, Nerd-Fonts-v2 codepoints remapped to FontAwesome/v3,

modules/home/rofi.nix

@@ -250,6 +250,14 @@ ${themeRows}
         # blueman-manager GUI (services.blueman.enable, system-side).
         exec blueman-manager ;;
 
+      printers)
+        # system-config-printer GUI (the CUPS admin app), installed by
+        # nomarchy.services.printing. Self-gated in the System menu; guard
+        # here too in case it's invoked directly.
+        command -v system-config-printer >/dev/null 2>&1 \
+          && exec system-config-printer
+        notify-send "Printers" "Not available (nomarchy.services.printing off?)."; exit 0 ;;
+
       audio)
         # PipeWire (pulse) sink/source switcher via rofi-pulse-select. Self-
         # gated in the System menu on the pulse socket; guarded here too.
@@ -360,6 +368,7 @@ ${themeRows}
           row "Bluetooth"      bluetooth
           [ -e "''${XDG_RUNTIME_DIR:-/run/user/$(id -u)}/pulse/native" ] \
             && row "Audio" audio-volume-high
+          command -v system-config-printer >/dev/null 2>&1 && row "Printers" printer
           row "Do Not Disturb" notification-disabled
           systemctl --user cat hyprsunset.service >/dev/null 2>&1 \
             && row "Night light" weather-clear-night
@@ -374,6 +383,7 @@ ${themeRows}
           *Network*)          exec "$0" network ;;
           *Bluetooth*)        exec "$0" bluetooth ;;
           *Audio*)            exec "$0" audio ;;
+          *Printers*)         exec "$0" printers ;;
           *"Do Not Disturb"*) exec "$0" dnd ;;
           *"Night light"*)    exec "$0" nightlight ;;
           *Snapshots*)        exec "$0" snapshot ;;
@@ -402,7 +412,7 @@ ${themeRows}
         esac ;;
 
       *)
-        echo "usage: nomarchy-menu [tools|system|power|power-profile|theme|clipboard|calc|files|emoji|web|network|bluetooth|audio|capture|keybinds|ask|dnd|nightlight|snapshot]" >&2
+        echo "usage: nomarchy-menu [tools|system|power|power-profile|theme|clipboard|calc|files|emoji|web|network|bluetooth|audio|printers|capture|keybinds|ask|dnd|nightlight|snapshot]" >&2
         exit 64 ;;
     esac
   '';

modules/nixos/services.nix

@@ -75,7 +75,8 @@ in
 
     printing.enable = lib.mkEnableOption ''
       CUPS printing with Avahi/mDNS, so network printers are auto-discovered
-      (add vendor drivers via `services.printing.drivers`)'';
+      (add vendor drivers via `services.printing.drivers`); the menu's
+      System ▸ Printers entry opens the system-config-printer GUI'';
 
     openrgb.enable = lib.mkEnableOption ''
       the OpenRGB daemon and GUI for controlling RGB lighting on peripherals
@@ -246,6 +247,9 @@ in
         nssmdns4 = true;
         openFirewall = true;
       };
+      # The CUPS admin GUI — the menu's System ▸ Printers entry execs it
+      # (self-gated on this binary), so it ships with the printing service.
+      environment.systemPackages = [ pkgs.system-config-printer ];
     })
 
     (lib.mkIf cfg.openrgb.enable {