feat(tools): Add window management tools

[CalvinAllen]

Description

Implement window management MCP tools to allow AI assistants to interact with Visual Studio windows.

Tools to Implement

• window_list - List all open windows
• window_activate - Activate/focus a specific window
• toolwindow_show - Show/hide tool windows (Solution Explorer, Error List, etc.)

VS APIs

• DTE2.Windows
• Window.Activate()
• DTE2.ExecuteCommand() for tool windows