fix: Local API requires docker exec when running with Docker Compose

[rud3ka]

Summary

Fixes incorrect instructions in create-super-administrator.md found during hands-on testing of the Docker Compose setup.

• Add warning: Local API is only accessible from within the Core container when running with Docker Compose — calling localhost:8080 directly from the host machine returns HTTP 401
• Add docker exec example: correct way to call Local API in a Docker Compose setup
• Fix URL scheme: https://localhost → http://localhost (Local API does not use TLS)
• Clarify context: label existing examples as "standalone deployment" to distinguish from Docker Compose

Test plan

• Follow create-super-administrator.md with a Docker Compose setup
• Verify that docker exec core curl ... successfully creates the admin
• Verify that calling localhost:8080 directly from host returns 401

🤖 Generated with Claude Code

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[3keyroman]

Hi @rud3ka , we do not support deployment using docker compose. This is rather description for the developer, when they are working with local environment. We support currently only Helm chart and virtual appliance.

[rud3ka]

Thank you for the clarification! You're right — the docker exec note is specific to the Docker Compose developer workflow and doesn't belong in the general installation guide. I'll close this PR. The fix has been applied where it's actually needed: in the development-environment README (PR #13) and in the QA local setup guide (PR #286).