Documentation for environment variables when using Docker Compose

### Documentation Type

CLI Reference

### Issue Type

Missing information

### Current Documentation Issue

I'm using keycloak-config-cli via Docker Compose and I'm having trouble using environment variables for JSON array fields (e.g. redirectUris, webOrigins).

The documentation shows how to use environment variables and JavaScript substitution when running the JAR directly, but it's unclear how this should work when using the Docker image with docker-compose and env_file.

For example, I have:
`CLIENT_REDIRECT_URIS=http://localhost:3000/api/auth/callback/keycloak,http://localhost:3001/api/auth/callback/keycloak`

and I'm trying to populate:
`"redirectUris": [...]`

However, the value is imported as a single string instead of being expanded into a JSON array.

Is there a supported way to "spread" or convert an environment variable into a JSON array when using the Docker image? It would be helpful if the documentation included a Docker/Docker Compose example for this use case, since the current examples only cover running the CLI as a JAR.

### Proposed Improvement

_No response_

### Target Audience

_No response_

### Additional Context

_No response_

No file is named. Start by reading the CLI Reference and Docker image documentation in the repository, then find where environment-variable/JAR examples are documented. Extend that section with a Docker Compose + env_file example showing how to set CLIENT_REDIRECT_URIS and similar array fields. Done when docs clearly show expected syntax/behavior so array fields import as JSON arrays instead of a single string.

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