Fix Docker socket access: add docker GID to PHP container group

The PHP container user needs the docker group to read the socket.
Uses DOCKER_GID env var in dev (defaults to 989) and dynamic GID
detection via Ansible stat in prod.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose-dev.yml

@@ -5,6 +5,8 @@ services:
       dockerfile: Dockerfile
     container_name: e_ticket_php
     restart: unless-stopped
+    group_add:
+      - "${DOCKER_GID:-989}"
     volumes:
       - .:/app
       - /var/run/docker.sock:/var/run/docker.sock:ro