feat(mcp-test-harness): implement server discovery and example generation

- Add real server discovery functionality that connects to MCP servers
- Query server capabilities through MCP initialization handshake
- Automatically discover tools, resources, and prompts using MCP list methods
- Generate complete server specifications with auto-generated test cases
- Create comprehensive example specifications for common server types:
  - Simple tool server example with basic echo functionality
  - Database server example with SQL tools and table resources
  - File system server example with file operations and security features
  - API wrapper server example with external API integration and prompts
- Include detailed README and usage documentation for examples
- Support automatic YAML generation with proper metadata and timestamps
- Add proper structured future markers instead of TODO comments

closes #123

Author: milliondreams