Add icon support for MCP tools

[jongalloway]

Overview

Add icons to MCP tools for improved AI assistant UX. The MCP C# SDK v0.6.0-preview.1 now supports icons on tools, resources, and prompts (#1096).

Background

Icons help AI assistants present tools more visually and can improve discoverability and user experience when browsing available tools.

Tasks

• Research available icon options and format requirements
• Define icon strategy by tool category:
  • template tools (e.g., 📋 or similar)
  • project tools (e.g., 📁)
  • package tools (e.g., 📦)
  • solution tools (e.g., 🗂️)
  • sdk tools (e.g., ⚙️)
• Prioritize high-visibility tools marked with [McpMeta("commonlyUsed", true)]
• Implement icons for commonly used tools first
• Consider server-level icon for dotnet-mcp itself
• Update documentation with icon usage guidelines

Implementation Notes

Refer to the EverythingServer example in the SDK: #1096

Parent Issue

Part of #322