Components: one look for every unit

The wdoc components under wdoc/component/ render every unit of a kind identically across projections — page structure lives in exactly one place.

Every unit page in every wskill looks the same because its structure is rendered by ONE wdoc_component, shared by all projections. wdoc/component/ holds one component per unit kind — concept_body, entity_body, fact_body, process_body — plus shared helpers (unit_examples, related_section, backlinks) and skill_md.wcl, the canonical SKILL.md body both the skill build and the book's skill preview render (so the preview can never drift from the shipped file).

A component declares wdoc_slots and a wdoc_body; the projection templates invoke it per unit (concept_body { unit = c examples = examples … }). The book and the skill pass different slot values — the book adds backlinks and two-column layout, the skill a back-to-index footer — but the page *structure* lives in exactly one place. Change the component and every page of that kind changes everywhere, in every view.

The same mechanism gives custom projections a native look: a new domain kind gets its own <kind>_body component next to the built-in ones, and its generated pages inherit the house style — heading, summary line, projected body, examples, related links — for free.

§ 1Examples

§ 1.1One component, every projection

The book and the skill invoke the same component with different slot values — page structure lives once.

// wdoc/book/main.wcl
concept_body { unit = c  examples = examples  all_units = all_units
               backlinks = referenced_by(c.id)  layout = "columns" }

// wdoc/skill/main.wcl — same component, skill-flavoured slots
concept_body { unit = c  examples = examples  all_units = all_units  backlinks = []
  p "[← All concepts](concepts_ref) · [← Back to SKILL.md](index)"
}