feat(tools): add solution/project management tools (add/remove project)

[CalvinAllen]

Description

Add tools to manage projects within a solution.

Tools to Implement

Tool	Description
solution_add_project	Add an existing project to the current solution
solution_remove_project	Remove a project from the current solution

Notes

• Extends existing solution tools category
• Competitor reference: Unofficial VS MCP Server by dhq-boiler