Primitive Run Cards

Each Retab primitive's result framed as a run card — a document thumbnail with a status pill and the primitive's output in the card body. Classification shows the page with its category and reasoning; split a mini page rail of color-keyed subdocuments; partition a keyed-chunk legend with an overlap ribbon; parse the page rendered as markdown; extract the page with each field's source box drawn over it. Composes the primitive-run-cards components over sample results.