@cssdoc/index

@cssdoc/index — a queryable semantic index over the @cssdoc/core model, plus the two cross-cutting concerns every downstream tool shares: a host-agnostic usage abstraction (so HTML, JSX, template literals, and CSS selectors all feed the same providers) and optional source spans (so diagnostics, hover ranges, and go-to-definition can point back into the CSS).

@cssdoc/core stays position-free; the spans are built here, in a dedicated PostCSS pass, and carried alongside the model. Build with createIndex (from CSS, with spans) or indexFromEntries (from a model snapshot, without spans).