Skill package setup — canonical layout & distribution

The source of truth for where a package's skills live and how they ship. Agent-agnostic; other tooling (e.g. wads-skillify) defers here for layout and spec compliance. Two flows: set up a new package, or migrate an existing one. Detail lives in the references — read on demand:

• references/canonical-layout-and-distribution.md — the discovery facts, the full distribution matrix, the SKILL.md spec, and the gh skill surface.
• references/migration-runbook.md — exact commands for both flows.

Golden rule: observe, don't invent. Every layout move is shown as a plan before it's applied; never break tests without asking.

Who discovers what (why layout matters)