v0.12.0

Added

• search_fields(domain, query) (progressive mode): BM25 over field
  names, descriptions and argument names — the shortcut for wide domains
  where reading the whole fragment costs more than searching for the one
  field you need. Field names come from endpoint function names (developer
  vocabulary, keyword-dense), so lexical search lands well without
  embeddings. Indexed lazily per domain, cached (schema is immutable).
  Measured on a 324-route app: a 1,743-token domain fragment collapses to
  a ~200-token search round trip.