[Studio] feat: add NameServer configuration drift detection

[yx9o]

What is the purpose of the change

Add a read-only tool for detecting configuration drift across NameServer nodes. This helps operators identify inconsistent runtime settings while preventing sensitive configuration values from being exposed.

Brief changelog

• Add a service for comparing allowlisted NameServer configuration properties across nodes.
• Add the rmq.nameserver.config.diff AI tool with input and output schemas.
• Report node reachability, check completeness, and configuration differences.
• Add unit tests, tool catalog validation, gateway validation, and API documentation.

Verifying this change

• cd server && mvn -Dtest=NameServerConfigDiffServiceTest,ToolGatewayServiceTest,ToolCatalogTest test
• cd server && mvn test
• git diff --check