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 ✅

telegraf.conf

@@ -41,23 +41,23 @@
   data_format = "json"
   qos = 0
 
-# Input: MQTT Consumer - BunkerM (DISABLED - auth fails, simulator not sending here)
-# [[inputs.mqtt_consumer]]
-#   servers = ["tcp://bunkerm-bunkerm-1:1900"]
-#   topics = [
-#     "airquality/#",
-#     "traffic/#",
-#     "parking/#",
-#     "noise/#",
-#     "weather/#",
-#     "light/#",
-#     "sensor/#",
-#     "smartcity/#"
-#   ]
-#   data_format = "json"
-#   qos = 0
-#   username = "bunker"
-#   password = "bunker"
+# Input: MQTT Consumer - BunkerM
+[[inputs.mqtt_consumer]]
+  servers = ["tcp://bunkerm-bunkerm-1:1900"]
+  topics = [
+    "airquality/#",
+    "traffic/#",
+    "parking/#",
+    "noise/#",
+    "weather/#",
+    "light/#",
+    "sensor/#",
+    "smartcity/#"
+  ]
+  data_format = "json"
+  qos = 0
+  username = "bunker"
+  password = "bunker"
 
 # Output: InfluxDB v2
 [[outputs.influxdb_v2]]