The view family

One data model, four projections: the book and the AI skill are standard; the presentation deck and the training book are optional.

A wskill's data renders into up to four *views*, each declared as an artifact block in wskill.wcl and built from its own template under wdoc/. The data is the single source; the views never carry topic content of their own.

View	Audience	What it is	Ships
Book	humans, reference	The comprehensive reference site — every unit gets a page, indexes shape the nav	always
AI skill	agents	SKILL.md + references/, filtered to :ai/:both content, with boundaries and parameters	always
Presentation	humans, first contact	An overview deck introducing the topic — slides feature existing units	optional
Training book	humans, learning	An ordered tutorial series with hands-on exercises and expected results	optional

The four serve different moments: the deck for *meeting* a topic, the training book for *learning* it, the book for *using* it day to day, and the skill for *an agent doing it for you*. Ship the optional two only when the topic warrants them — declaring the artifact and authoring data/presentation/ or data/training/ is all it takes.