Created MAC governance skills and publication model

Property	Value
description	Added the shared governance skill layer and the source-to-published documentation model.
version	0.4.0
type	Create
related	MAC, Workflow Model

• Added the shared .codex context and reusable cross-repo skills that now live in mac instead of being duplicated informally across product repos.
• Defined the publication split between source doctrine in mac, published product/governance docs in mac-docs, and thin local .codex layers in product repos.
• Pilot-aligned mac-cli, mac-core, and mac-mcp with the new governance source model.