Extract verified link data from chunk[chunk_pos..end_offset), then emit via parser: on_a(true,...), process_inline(link_text), on_a(false,...). seq_pos = byte after the 3-char lead [??; end_offset = byte after the link (e.g. after ')' for inline, after ']' for reference). Sets is_reference true for reference-style; then href is the ref label (consumer resolves to URL).