dify - 💡(How to fix) Fix [Refactor/Chore] Clean up stale Docker env examples [1 pull requests]

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Description

Clean up stale Docker environment example entries so the documented variables match the configuration that Dify and Docker Compose actually consume.

The update should:

• apply MYSQL_MAX_CONNECTIONS in the MySQL Compose command instead of hardcoding 1000
• rename the VikingDB example variable from VIKINGDB_SCHEMA to the code-supported VIKINGDB_SCHEME
• remove unused prompt/code generation token limit examples
• remove the unused ENFORCE_LANGGENIUS_PLUGIN_SIGNATURES plugin signature example

Motivation

Several Docker example variables are currently misleading because they are misspelled, not consumed, or not wired into the Compose command they describe. This can confuse self-hosted users who copy .env.example or middleware.env.example while configuring deployments.

Additional Context

This is a Docker configuration example cleanup only.