flow: add Dual Outlet - Couch to single-press button automation

Dual plug only responds to per-channel state_1/state_2 commands, not the
shared {state:TOGGLE} payload. Route single-filter through a couch-mapper
that emits {"state_1":"TOGGLE","state_2":"TOGGLE"} so both outlets flip.

Also adds state-in node, /set out node, and dashboard widget showing
state_1/state_2. Verified E2E + 567 Rego checks pass.

Refs: david/nr-flow-validator#2

flows/zigbee-monitor.yaml

@@ -10,6 +10,7 @@ single_plugs:
   - Squiggle
   - Sideboard Lamp
   - Bamboo Lights
+  - Dual Outlet - Couch
 
 # Plugs toggled on press-hold-release (action: "release" after a "hold")
 hold_plugs:
@@ -53,6 +54,12 @@ flows:
         topic: zigbee2mqtt/DJ Booth
         qos: 0
 
+      - id: zigbee-state-couch
+        type: mqtt in
+        broker: mosquitto
+        topic: zigbee2mqtt/Dual Outlet - Couch
+        qos: 0
+
       - id: button-in
         type: mqtt in
         broker: mosquitto
@@ -113,6 +120,18 @@ flows:
         broker: mosquitto
         topic: zigbee2mqtt/DJ Booth/set
 
+      - id: couch-mapper
+        type: function
+        name: Toggle both outlets
+        code: |
+          msg.payload = { state_1: 'TOGGLE', state_2: 'TOGGLE' };
+          return msg;
+
+      - id: plug-out-couch
+        type: mqtt out
+        broker: mosquitto
+        topic: zigbee2mqtt/Dual Outlet - Couch/set
+
       - id: text-squiggle
         type: ui-text
         group: Plugs
@@ -141,6 +160,13 @@ flows:
         format: "{{msg.payload.state}}"
         order: 4
 
+      - id: text-couch
+        type: ui-text
+        group: Plugs
+        label: Dual Outlet - Couch
+        format: "{{msg.payload.state_1}} / {{msg.payload.state_2}}"
+        order: 6
+
       - id: permit-btn
         type: ui-button
         group: Plugs
@@ -160,7 +186,9 @@ flows:
       zigbee-state-sideboard: [text-sideboard]
       zigbee-state-bamboo: [text-bamboo]
       zigbee-state-djbooth: [text-djbooth]
+      zigbee-state-couch: [text-couch]
       button-in: [single-filter, hold-filter]
-      single-filter: [plug-out-squiggle, plug-out-sideboard, plug-out-bamboo]
+      single-filter: [plug-out-squiggle, plug-out-sideboard, plug-out-bamboo, couch-mapper]
+      couch-mapper: [plug-out-couch]
       hold-filter: [plug-out-djbooth]
       permit-btn: [mqtt-out]