FEATURE] Persist stack connection details beyond terminal session

Is your feature request related to a problem?

When the observability stack is deployed via docker compose up, all connection details (endpoints, ports, dashboard credentials) are printed to the terminal. If the terminal session is closed or scrollback is lost, there is no way to retrieve this information without inspecting individual Docker containers or config files manually.

This is especially painful when:

• Returning to the stack after a break and needing to remember the OpenSearch Dashboards URL, username, and password
• Sharing the stack setup with a teammate who wasn't present during deployment
• Reattaching to a long-running stack after a terminal crash or SSH disconnect

Describe the solution you'd like

Provide a persistent and easily accessible way to retrieve stack connection details after deployment. Some options:

1. docker compose info command or script — A ./stack-info.sh script (or make info target) that prints all endpoints, ports, and credentials at any time by reading from the compose config and .env files
2. Write connection details to a file — On startup, generate a stack-info.txt or stack-info.json in the project root with all relevant connection details:

   {
     "opensearch": {"url": "https://localhost:9200", "username": "admin", "password": "..."},
     "dashboards": {"url": "http://localhost:5601"},
     "otel_collector": {"grpc": "localhost:4317", "http": "localhost:4318"},
     "prometheus": {"url": "http://localhost:9090"},
     "data_prepper": {"url": "http://localhost:21890"}
   }
   

Start by reviewing the Docker Compose configuration and .env files referenced in the issue, along with the current deployment output. Clarify whether the project should provide an info command, a generated file, or both. Done means connection details remain accessible after deployment and include the listed endpoints, ports, and credentials.