feat: add mailgun-webhook service to docker-compose configurations

- Add mailgun-webhook service to both standalone and swarm deployments
- Configure service with Prometheus monitoring and debug logging
- Route traffic through Traefik at webhook.rezije.app
- Use version-controlled image with MAILGUN_WEBHOOK_VERSION variable

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docker-stack/docker-compose-standalone.yaml

@@ -79,3 +79,21 @@ services:
       - traefik.http.routers.mongo-express.entrypoints=http
       - traefik.http.routers.mongo-express.rule=Host(`mongo.rezije.app`)
 
+  mailgun-webhook:
+    image: registry.budakova.org/mailgun-webhook-service:${MAILGUN_WEBHOOK_VERSION:-latest}
+    networks:
+      - traefik-network
+    environment:
+      PORT: 3000
+      PROMETHEUS_APP_LABEL: mailgun-webhook-service
+      PROMETHEUS_HISTOGRAM_BUCKETS: 0.1,0.5,1,5,10
+      DEBUG: server:*,app:*
+    container_name: evidencija-rezija__mailgun-webhook
+    restart: unless-stopped
+    labels:
+      - traefik.enable=true
+      - traefik.docker.network=traefik-network
+      - traefik.http.services.mailgun-webhook.loadbalancer.server.port=3000
+      - traefik.http.routers.mailgun-webhook.entrypoints=http
+      - traefik.http.routers.mailgun-webhook.rule=Host(`webhook.rezije.app`)
+

docker-stack/docker-compose-swarm.yml

@@ -79,3 +79,24 @@ services:
         - traefik.http.routers.mongo-express.entrypoints=http
         - traefik.http.routers.mongo-express.rule=Host(`mongo.rezije.app`)
 
+  mailgun-webhook:
+    image: registry.budakova.org/mailgun-webhook-service:${MAILGUN_WEBHOOK_VERSION:-latest}
+    networks:
+      - traefik-network
+    environment:
+      PORT: 3000
+      PROMETHEUS_APP_LABEL: mailgun-webhook-service
+      PROMETHEUS_HISTOGRAM_BUCKETS: 0.1,0.5,1,5,10
+      DEBUG: server:*,app:*
+    deploy:
+      restart_policy:
+        condition: any
+        delay: 5s
+        max_attempts: 0
+      labels:
+        - traefik.enable=true
+        - traefik.docker.network=traefik-network
+        - traefik.http.services.mailgun-webhook.loadbalancer.server.port=3000
+        - traefik.http.routers.mailgun-webhook.entrypoints=http
+        - traefik.http.routers.mailgun-webhook.rule=Host(`webhook.rezije.app`)
+