v1.3.1 — fix: WS score frames nest the score object

Fixed

• WebSocket score frames parsed as all-None. The wire nests the score object — a frame is {"type": "score", "match_id": N, "score": {sets, games, points, server, is_tiebreak, timestamp, win_probability_p1?, danger?}} with the ULTRA model fields inside the score object — but ScoreUpdate.from_dict built its Score from the whole frame. On real frames every field of update.score came back None. The nested object is now parsed when present; the inline read remains only as a defensive fallback for flat emitters. break_point / break_point_result frames are flat on the wire and were never affected.

If you consume the live feed on 1.3.0, upgrade.