fix: support icons in registerTool config and tools/list response

[Yanhu007]

Summary

Fixes #1864

The MCP spec's ToolSchema includes icons (via IconsSchema), but McpServer.registerTool() has two gaps:

1. The config parameter type does not accept icons
2. The tools/list handler does not include icons in the tool definition

Changes

• Add icons?: Tool['icons'] to registerTool config type
• Add icons parameter to _createRegisteredTool
• Include icons in the toolDefinition built by the tools/list handler
• Add icons to the RegisteredTool type

Usage

server.registerTool(
  'my-tool',
  {
    description: 'A tool with an icon',
    icons: [{ src: 'https://example.com/icon.png', mimeType: 'image/png' }],
  },
  async () => ({ content: [{ type: 'text', text: 'hello' }] })
);

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🦋 Changeset detected

Latest commit: 8c763a2

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
@modelcontextprotocol/server	Patch
@modelcontextprotocol/express	Patch
@modelcontextprotocol/fastify	Patch
@modelcontextprotocol/hono	Patch
@modelcontextprotocol/node	Patch

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commit: 8c763a2