v2.5.1

Fixed

• extract_page { prompt: "schematron" } no longer sends response_format. Measured against a locally served open-weight Schematron-8B on mlx_vlm.server (llguidance-constrained decoding): with response_format present, a real CNN zone came back as {"stories": []} in 6 completion tokens; the IDENTICAL messages with response_format omitted returned valid, schema-conformant JSON with 5 stories in 285 tokens. A 3-link toy page worked either way, so the collapse only shows on real markup. The schema already rides inline in the schematron prompt, so constrained decoding on top of it was redundant and, on real pages, actively harmful; response_format is now omitted entirely (never sent as null) in schematron mode, unchanged in html mode. Since nothing constrains the shape server-side anymore in schematron mode, extractPage now also rejects a syntactically valid but non-object JSON response (array/null/primitive) with the same invalid-JSON error shape. One new unit test pins html mode still sending response_format; the existing schematron wire-shape test now asserts its absence (test/extract.test.ts).