MCP tools: project and role management

[The127]

Summary

Add MCP tools for managing projects and roles within a virtual server.

Depends on #232.

Tools

Tool	API Endpoint	Description
list_projects	GET /{vs}/projects	List projects
get_project	GET /{vs}/projects/{slug}	Project detail
create_project	POST /{vs}/projects	Create a new project
list_roles	GET /{vs}/projects/{slug}/roles	List roles in a project
get_role	GET /{vs}/projects/{slug}/roles/{id}	Role detail
create_role	POST /{vs}/projects/{slug}/roles	Create a role (name, description)
update_role	PATCH /{vs}/projects/{slug}/roles/{id}	Update role name/description
list_users_in_role	GET /{vs}/projects/{slug}/roles/{id}/users	List users assigned to a role