Defined MAC MCP role and boundaries

Property	Value
description	Documented `MAC MCP` as the runtime and integration layer rather than the governance source.
version	0.1.0
related	MAC MCP, Repo Boundaries

• Documented MAC MCP as the runtime and integration layer for MCP-facing capabilities, not as the ecosystem governance source.
• Captured the non-goals for the first pass, including no fake server implementation and no oversized local skill catalog.
• Kept the public docs intentionally lightweight until the runtime surface becomes real.