[Feature]: (mcp): Add elicitation support to McpClientBuilder and ClientCapabilities

[miniceM]

Currently, AgentScope Java's McpClientBuilder does not support the elicitation capability defined in the official MCP Java SDK.

According to the https://modelcontextprotocol.io/sdk/java/mcp-client#elicitation-support, elicitation is a client capability that allows MCP servers to request additional information from clients during tool execution.

Expected Behavior:
// Official SDK usage (from documentation)
var client = McpClient.sync(transport)
.capabilities(ClientCapabilities.builder()
.elicitation() // Enable elicitation capability
.build())
.elicitation(elicitationHandler) // Register elicitation handler
.build();

Current Status:
In io.agentscope.core.tool.mcp.McpClientBuilder (lines 303-304, 334-335):
McpSchema.ClientCapabilities clientCapabilities =
McpSchema.ClientCapabilities.builder().build();
Missing:

1. .elicitation() method in ClientCapabilities.builder()
2. .elicitation(handler) method in McpAsyncClient/McpSyncClient builders
3. ElicitRequest import and usage
4. ElicitResult import and usage