Split button: single→3 plugs, hold-release→DJ Booth only

zigbee-monitor.yaml:
- Single click (action=single) toggles Squiggle, Sideboard Lamp,
  Bamboo Lights
- Press-hold-release (action=release after hold) toggles DJ Booth
  only
- Two filter functions: "Single click" and "Hold release", button-in
  fan-out wires to both
- DJ Booth added to zigbee-state-in and ui-text widgets for visibility
- "plugs:" list replaced with "single_plugs:" and "hold_plugs:" for
  declarative clarity (generator doesn't use them, but documents intent)

infra/zigbee2mqtt/configuration.yaml:
- Removed DJ Booth from "all_plugs" group (now Squiggle, Sideboard
  Lamp, Bamboo Lights only)
- Pushed same change to live /root/zigbee2mqtt/configuration.yaml and
  restarted zigbee2mqtt container

Diagnostics in justfile + scripts/:

justfile:
- Constants: RPI_HOST, MQTT_HOST, MQTT_PORT, RPI_DIR, NR_PORT
- rpi, mqtt-pub, mqtt-sub, mqtt-watch, mqtt-button
- nr-show, nr-diff, nr-logs, nr-editor, nr-dashboard
- z2m-devices, z2m-logs, z2m-state
- mqtt-logs, restart, restart-all

scripts/mqtt.py:
- MQTT publish/subscribe/watch helpers using paho-mqtt v2.x
- Run via uv run --with paho-mqtt (no global install needed)

scripts/diag.py:
- nr-show: live flow summary with mqtt-out topic list
- nr-diff: structural diff deployed vs repo, normalizes random uuids
- z2m-devices: paired devices + group membership
- mqtt-button: publish action and watch /set topics (E2E test)

Verified end-to-end via `just mqtt-button`:
  single  → 3 messages on .../set (Squiggle, Sideboard Lamp, Bamboo Lights)
  release → 1 message on .../set (DJ Booth)

justfile

@@ -79,3 +79,78 @@ watch FLOW="zigbee-monitor":
 new NAME:
     @cp flows/zigbee-monitor.yaml flows/{{NAME}}.yaml
     @echo "Created flows/{{NAME}}.yaml — edit and run 'just validate {{NAME}}'"
+
+# ---- Diagnostics ----
+# All commands target the live RPi at $RPI_HOST (default root@192.168.81.147).
+# Override with: just RPI_HOST=user@host mqtt-pub topic msg
+
+RPI_HOST := "root@192.168.81.147"
+MQTT_HOST := "192.168.81.147"
+MQTT_PORT := "1883"
+RPI_DIR := "/root"
+NR_PORT := "1880"
+
+# Run a command on the RPi over SSH
+rpi CMD *ARGS:
+    ssh -o ConnectTimeout=5 {{RPI_HOST}} '{{CMD}} {{ARGS}}'
+
+# Publish to MQTT broker on the RPi
+mqtt-pub TOPIC PAYLOAD:
+    uv run --with paho-mqtt python3 scripts/mqtt.py pub --topic '{{TOPIC}}' --payload '{{PAYLOAD}}'
+
+# Subscribe to MQTT broker on the RPi for N seconds
+mqtt-sub TOPIC SECONDS="5":
+    uv run --with paho-mqtt python3 scripts/mqtt.py sub --topic '{{TOPIC}}' --seconds {{SECONDS}}
+
+# Publish a button action and watch what /set topics fire (E2E test)
+mqtt-button ACTION="single":
+    uv run --with paho-mqtt python3 scripts/diag.py mqtt-button --action {{ACTION}}
+
+# Show live Node-RED flow summary (node count, function names, button wires, mqtt-out topics)
+nr-show:
+    python3 scripts/diag.py show
+
+# Diff deployed Node-RED flow against repo (excluding random uuid ids)
+nr-diff FLOW="zigbee-monitor": generate
+    python3 scripts/diag.py diff output/{{FLOW}}.json
+
+# Tail Node-RED container logs
+nr-logs:
+    ssh {{RPI_HOST}} 'docker logs --tail 50 -f nodered'
+
+# Tail zigbee2mqtt container logs
+z2m-logs:
+    ssh {{RPI_HOST}} 'docker logs --tail 50 -f zigbee2mqtt'
+
+# Tail mosquitto container logs
+mqtt-logs:
+    ssh {{RPI_HOST}} 'docker logs --tail 50 -f mosquitto'
+
+# Restart a service container
+restart SERVICE:
+    ssh {{RPI_HOST}} 'docker restart {{SERVICE}}'
+
+# Restart the full stack
+restart-all:
+    ssh {{RPI_HOST}} 'docker restart mosquitto zigbee2mqtt nodered'
+
+# Show paired zigbee devices and their friendly names
+z2m-devices:
+    ssh {{RPI_HOST}} 'cat {{RPI_DIR}}/zigbee2mqtt/configuration.yaml' > /tmp/z2m.yaml
+    python3 scripts/diag.py z2m-devices /tmp/z2m.yaml
+
+# Show per-device persisted state from z2m
+z2m-state:
+    ssh {{RPI_HOST}} 'cat {{RPI_DIR}}/zigbee2mqtt/state.json' | python3 -m json.tool | head -60
+
+# Open the Node-RED editor
+nr-editor:
+    xdg-open http://{{MQTT_HOST}}:{{NR_PORT}} 2>/dev/null || open http://{{MQTT_HOST}}:{{NR_PORT}} 2>/dev/null || echo "Open: http://{{MQTT_HOST}}:{{NR_PORT}}"
+
+# Open the Dashboard 2.0 SPA
+nr-dashboard:
+    xdg-open http://{{MQTT_HOST}}:{{NR_PORT}}/dashboard 2>/dev/null || open http://{{MQTT_HOST}}:{{NR_PORT}}/dashboard 2>/dev/null || echo "Open: http://{{MQTT_HOST}}:{{NR_PORT}}/dashboard"
+
+# Watch live MQTT traffic (matches the z2m base_topic by default)
+mqtt-watch TOPIC="zigbee2mqtt/#":
+    uv run --with paho-mqtt python3 scripts/mqtt.py watch --topic '{{TOPIC}}'