v0.4.0

• Added OddsLine.is_active (bool, default true) — false = market suspended/closed with the price frozen (OpticOdds locked-odds parity; absent treated as true).
• Changed OddsLine.timestamp / ArbitrageLeg.timestamp documented as the delivery / feed-freshness timestamp — advances every ingest cycle, matching OpticOdds' timestamp. The API now populates this field (previously always null); it is NOT a price-last-changed time. The removed odds_changed_at/last_seen_at/wire_received_at were never modeled by this SDK. (SHA-1048)