feat(dnd): swaync Do-Not-Disturb toggle + Waybar bell indicator

Adds a Do-Not-Disturb story on top of swaync:

- Waybar `custom/notification` module via `swaync-client -swb` — streams
  the notification count + DND state (no polling). Left-click toggles the
  panel, right-click toggles DND; bell-off glyph + muted color when DND is
  on, accent when notifications are waiting.
- `nomarchy-menu dnd` toggle in the root picker and bound to SUPER+CTRL+D
  (so it shows in the SUPER+? cheatsheet). Turning DND off confirms with a
  toast; turning it on is silent — notifications are suppressed and the
  bell-off icon is the cue.

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

modules/home/waybar.nix

@@ -66,7 +66,7 @@ let
 
     modules-left = [ "hyprland/workspaces" "hyprland/window" ];
     modules-center = [ "clock" ];
-    modules-right = [ "tray" "pulseaudio" "network" "cpu" "memory" "custom/powerprofile" "battery" ];
+    modules-right = [ "tray" "pulseaudio" "network" "cpu" "memory" "custom/powerprofile" "battery" "custom/notification" ];
 
     "hyprland/workspaces" = {
       format = "{icon}";
@@ -118,6 +118,31 @@ let
       on-click = "${powerProfileCycle}";
     };
 
+    # swaync notification bell + Do-Not-Disturb state. `-swb` streams JSON
+    # (text/tooltip/class) on every change, so it tracks count and DND with
+    # no polling. Left-click toggles the panel; right-click toggles DND.
+    # The `dnd-*` classes (bell-off glyph) are styled muted below.
+    "custom/notification" = {
+      exec = "swaync-client -swb";
+      return-type = "json";
+      exec-if = "which swaync-client";
+      format = "{icon}";
+      format-icons = {
+        none = "󰂜";
+        notification = "󰂚";
+        dnd-none = "󰂛";
+        dnd-notification = "󰂛";
+        inhibited-none = "󰂜";
+        inhibited-notification = "󰂚";
+        dnd-inhibited-none = "󰂛";
+        dnd-inhibited-notification = "󰂛";
+      };
+      on-click = "swaync-client -t -sw";
+      on-click-right = "swaync-client -d -sw";
+      tooltip = true;
+      escape = true;
+    };
+
     tray.spacing = 8;
   };
 
@@ -164,11 +189,16 @@ let
       font-weight: bold;
     }
 
-    #tray, #pulseaudio, #network, #cpu, #memory, #custom-powerprofile, #battery {
+    #tray, #pulseaudio, #network, #cpu, #memory, #custom-powerprofile, #battery, #custom-notification {
       color: @subtext;
       padding: 0 10px;
     }
 
+    /* notifications waiting → accent; Do-Not-Disturb → muted bell-off */
+    #custom-notification.notification { color: @accent; }
+    #custom-notification.dnd-none,
+    #custom-notification.dnd-notification { color: @muted; }
+
     #pulseaudio.muted { color: @muted; }
     #battery.warning { color: @warn; }
     #battery.critical { color: @bad; }