feat: migrate InfluxDB and Grafana from digital-twin/ to smart-city/ stack

- docker-compose.influxdb.yml: InfluxDB v2 on smartcity-shared + traefik-public
- docker-compose.grafana.yml: Grafana 10.2 on smartcity-shared + traefik-public
- grafana/provisioning/: dashboards + datasources updated for smart-city
- pulsar/docker-compose.yml: added smartcity-shared network for simulator access

Services migrated (preserving existing volumes):
  - digital-twin-influxdb → smart-city-influxdb
  - digital-twin-grafana  → smart-city-grafana

Traefik routes updated:
  - influxdb.digitribe.fr → smart-city-influxdb:8086
  - grafana.digitribe.fr  → smart-city-grafana:3000

docker-compose.grafana.yml

@@ -0,0 +1,38 @@
+# Grafana - Visualization dashboards for Smart City Digital Twin Martinique
+# Usage: docker compose -f docker-compose.grafana.yml up -d
+# Note: run from the project root or pass -p smart-city to attach to the smart-city project
+
+networks:
+  smartcity-shared:
+    external: true
+  traefik-public:
+    external: true
+
+volumes:
+  grafana_data:
+    external: false
+    name: digital-twin_grafana_data
+
+services:
+  grafana:
+    image: grafana/grafana:10.2.0
+    container_name: smart-city-grafana
+    networks:
+      - smartcity-shared
+      - traefik-public
+    ports:
+      - "3001:3000"
+    environment:
+      # Anonymous auth - must match the org name in Grafana's database
+      - GF_AUTH_ANONYMOUS_ENABLED=true
+      - GF_AUTH_ANONYMOUS_ORG_NAME=Digitribe
+      - GF_AUTH_ANONYMOUS_ORG_ROLE=Admin
+      # Admin credentials
+      - GF_SECURITY_ADMIN_USER=admin
+      - GF_SECURITY_ADMIN_PASSWORD=Digitribe972
+      # Plugins
+      - GF_INSTALL_PLUGINS=grafana-piechart-panel,grafana-simple-json-datasource
+    volumes:
+      - grafana_data:/var/lib/grafana
+      - ./grafana/provisioning:/etc/grafana/provisioning
+    restart: unless-stopped