enh(shopware): improve healthchecks and proxy configuration

Removed obsolete EXPOSE/healthcheck from Dockerfile and added robust service-specific healthchecks:

- web: HTTP robots.txt check

- worker/scheduler: php -v runtime check

- opensearch: cluster health API check

Added TRUSTED_PROXIES=* for proxy-aware headers and centralized OPENSEARCH_PORT in vars.

Context: discussed implementation details in ChatGPT conversation on 2025-11-06 — https://chatgpt.com/share/690c9fb3-79f4-800f-bbdf-ea370c8f142c

roles/web-app-shopware/vars/main.yml

@@ -28,9 +28,12 @@ SHOPWARE_WORKER_ENTRYPOINT:     "{{ applications | get_app_conf(application_id,
 SHOPWARE_SCHED_ENTRYPOINT:      "{{ applications | get_app_conf(application_id, 'docker.services.scheduler.entrypoint') }}"
 SHOPWARE_WORKER_REPLICAS:       "{{ applications | get_app_conf(application_id, 'docker.services.worker.replicas') }}"
 
-# Search/Cache
+# Redis Cache
 SHOPWARE_REDIS_ENABLED:               "{{ applications | get_app_conf(application_id, 'docker.services.redis.enabled') }}"
 SHOPWARE_REDIS_ADDRESS:               "redis:6379"
+
+# Opensearch
+SHOPWARE_OPENSEARCH_PORT:             "9200"
 SHOPWARE_OPENSEARCH_ENABLED:          "{{ applications | get_app_conf(application_id, 'docker.services.opensearch.enabled') }}"
 SHOPWARE_OPENSEARCH_IMAGE:            "{{ applications | get_app_conf(application_id, 'docker.services.opensearch.image') }}"
 SHOPWARE_OPENSEARCH_VERSION:          "{{ applications | get_app_conf(application_id, 'docker.services.opensearch.version') }}"