webrain_extract (mode: autoschema) detects repeated container patterns on
the page and returns candidate base-selectors — e.g. .product, li.item.
Zero LLM.
Set adaptive: true to auto-relocate the container when the base selector
matches nothing (site redesigned) — it finds elements still containing ≥2 of
the field selectors.
Never reach for webrain_observe (what: html) for page text.webrain_observe (what: state / clean), webrain_eval, and the
extractors return text/structure far cheaper. html is the LAST resort —
only when the task explicitly asks for raw markup.
