feat: add Prometheus metrics and Grafana dashboard for system health monitoring

Agent-Logs-Url: https://github.com/christianlouis/pop_puller_to_gmail/sessions/11ac4536-eaad-44fe-920c-e8306918f06f

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

docker-compose.new.yml

@@ -101,6 +101,44 @@ services:
       - backend
     restart: unless-stopped
 
+  # Prometheus metrics collection
+  prometheus:
+    image: prom/prometheus:v2.51.2
+    container_name: pop3-prometheus
+    ports:
+      - "9090:9090"
+    volumes:
+      - ./monitoring/prometheus.yml:/etc/prometheus/prometheus.yml:ro
+      - prometheus_data:/prometheus
+    command:
+      - "--config.file=/etc/prometheus/prometheus.yml"
+      - "--storage.tsdb.path=/prometheus"
+      - "--storage.tsdb.retention.time=30d"
+      - "--web.enable-lifecycle"
+    depends_on:
+      - backend
+    restart: unless-stopped
+
+  # Grafana dashboards
+  grafana:
+    image: grafana/grafana:10.4.3
+    container_name: pop3-grafana
+    ports:
+      - "3001:3000"
+    environment:
+      - GF_SECURITY_ADMIN_USER=admin
+      - GF_SECURITY_ADMIN_PASSWORD=admin
+      - GF_USERS_ALLOW_SIGN_UP=false
+    volumes:
+      - grafana_data:/var/lib/grafana
+      - ./monitoring/grafana/provisioning:/etc/grafana/provisioning:ro
+      - ./monitoring/grafana/dashboards:/etc/grafana/dashboards:ro
+    depends_on:
+      - prometheus
+    restart: unless-stopped
+
 volumes:
   postgres_data:
   redis_data:
+  prometheus_data:
+  grafana_data: