[Feature] Dubbo MCP Authentication Support

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### Search before asking

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### Apache Dubbo Component

Java SDK (apache/dubbo)

### Descriptions

To ensure secure communication between clients and the registry through the Dubbo MCP protocol, we plan to introduce an authentication mechanism. This will help prevent unauthorized access and allow integration with existing security infrastructures.

### Related issues

_No response_

### Are you willing to submit a pull request to fix on your own?

- [ ] Yes I am willing to submit a pull request on my own!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

No files, tests, or entry points are specified. Start by locating the Java SDK's Dubbo MCP client and registry communication code, then determine the authentication design and integration points. Done means clients and the registry authenticate securely through the Dubbo MCP protocol without unauthorized access.

Written by the indexing model from the issue text.