chore: update mailgun-webhook service URL to mailgun-webhook.rezije.app

- Change from webhook.rezije.app to mailgun-webhook.rezije.app for clarity
- Update both standalone and swarm configurations

🤖 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

@@ -95,5 +95,5 @@ services:
       - 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`)
+      - traefik.http.routers.mailgun-webhook.rule=Host(`mailgun-webhook.rezije.app`)
 

docker-stack/docker-compose-swarm.yml

@@ -98,5 +98,5 @@ services:
         - 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`)
+        - traefik.http.routers.mailgun-webhook.rule=Host(`mailgun-webhook.rezije.app`)