feat: activate BunkerM MQTT broker + fix Telegraf

- BunkerM: recreated with port 1883 (external) -> 1900 (internal)
- BunkerM: disabled dynsec plugin, using password_file auth (bunker/bunker)
- Simulator: ENABLE_BUNKER=1, BUNKERM_PORT=1900
- Telegraf: reactivated BunkerM consumer on port 1900
- Telegraf: recreated container (3 MQTT consumers connected)
- Grafana: dashboard v4 with corrected Flux queries
- Grafana: datasource fixed (bucket=smartcity, token=my-super-token)

Verified:
- Simulator publishes to EMQX ✅, Mosquitto ✅, BunkerM ✅
- Telegraf receives from all 3 brokers ✅
- InfluxDB has data from all brokers ✅
- Grafana dashboard displays data ✅

simulator.py

@@ -646,7 +646,7 @@ def publish_bunkerm(sid: str, sensor: dict, values: dict) -> bool:
     import base64, http.cookiejar, urllib.request, json
     from datetime import datetime, timezone
 
-    host = "bunkerm_bunkerm_1:2000"
+    host = "bunkerm-bunkerm-1:2000"
     login_url = f"http://{host}/login"
     data_url = f"http://{host}/api/sensors/data"