fix: add support to set server instructions

[codezjx]

Motivation and Context

Fix #98 , we need to provide a method to set server instructions, which needs to be the same as the python sdk

How Has This Been Tested?

Already tested on sync and async server:

McpSyncServer server = McpServer.sync(transport)
    .serverInfo("stdio-server-example", "1.0.0")
    .instructions("This is a simple MCP server example that provides two tools: xxxx.")
    .tool(xxx)
    .build();

The server can return instructions normally:

20:53:05.009 [pool-1-thread-1] INFO i.m.client.McpAsyncClient - Server response with Protocol: 2024-11-05, Capabilities: ServerCapabilities[experimental=null, logging=LoggingCapabilities[], prompts=null, resources=null, tools=ToolCapabilities[listChanged=false]], Info: Implementation[name=stdio-server-async-example, version=1.0.0] and Instructions This is a simple MCP server example that provides two tools: xxxx.

And the build was success:

[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for Java SDK MCP Parent 0.9.0-SNAPSHOT:
[INFO]
[INFO] Java SDK MCP Parent ................................ SUCCESS [ 0.410 s]
[INFO] Java SDK MCP BOM ................................... SUCCESS [ 0.016 s]
[INFO] Java MCP SDK ....................................... SUCCESS [ 4.308 s]
[INFO] Tests for the Java MCP SDK ......................... SUCCESS [ 0.310 s]
[INFO] WebFlux implementation of the Java MCP SSE transport SUCCESS [ 1.222 s]
[INFO] Spring Web MVC implementation of the Java MCP SSE transport SUCCESS [ 1.101 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 7.432 s
[INFO] Finished at: 2025-04-01T20:59:09+08:00
[INFO] ------------------------------------------------------------------------

Breaking Changes

Users do not need to modify their original code if they do not need to set instructions

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[tzolov]

LGTM

[tzolov]

Thank you @codezjx
Nice catch and proper fix.

[codezjx]

@tzolov Happy to contribute! Thanks for the quick merge 🚀