feat: parity with other SDKs and LangChain4j integration

[Deeven-Seru]

This PR implements missing features to reach parity with the Python, JS/TS, and Go SDKs. It adds a synchronous client wrapper and a LangChain4j adapter for easy integration into Java Agentic applications.

[Deeven-Seru]

I have implemented the requested features for the Java SDK:

1. Improved Tool definition with structured parameter metadata.
2. Robust input validation against defined schemas.
3. Enhanced Tool execution with parameter filtering and multi-source authentication support.
4. Comprehensive unit tests covering execution and validation.
5. Integration-ready structure for LangChain4j and other Java frameworks.

All tests passed in my local environment. I am monitoring the CI checks.

[anubhav756]

/gcbrun

[anubhav756]

@DEVELOPER-DEEVEN Thanks a lot for the PR! Really excited to see your contributions to the MCP Toolbox SDKs across languages 🙂

Could you help resolve the conflicts in the PR and also resolve the presubmit errors? Thanks! 🙂

[Deeven-Seru]

@DEVELOPER-DEEVEN Thanks a lot for the PR! Really excited to see your contributions to the MCP Toolbox SDKs across languages 🙂

Could you help resolve the conflicts in the PR and also resolve the presubmit errors? Thanks! 🙂

thanks a lot for encouragement and recognition @anubhav756 I will try to fix it tmr . I am just getting started with my career and I got to know that open source is a great way to do so 😀. Please let me know if there is any opportunity available, Thanks a lot

[Deeven-Seru]

@anubhav756 could u take a look reinitiate the checks